Bologna Centrale Terminal

Here's a website that might help. Not sure if there's a link to a map on the site, but looks like a lot of specific info: https://showmethejourney.com/train-station-guide/station/14-bolognacentrale

It's a labyrinth of underground tracks (16 to 19) used by high speed trains and two satellite areas for the local trains: I doubt you can make it in 15 minutes.
If your train stops at the underground tracks, You must take the stairs and keep on going up till you see the sky. Once outdoor, Be aware that platform 1 and platform 1Ovest have different names because they are different platforms.

On the plus side if you purchased a through ticket on the official site and you miss the Regionale, you can use the same ticket to freely get on the next Regionale making the same route.

What are the codes and times of the 2 trains you are taking?

Dario, I dont have the train numbers. I am still in the planning stages.

You'll have to find the intended arrival and departure tracks by yourself here: https://prm.rfi.it/qo_prm/QO_Partenze_SiPMR.aspx?Id=635&lin=it&dalle=07.00&alle=07.59&ora=07.00&guid=

As I wrote above, missing a Regionale is not a tragedy. Pick the regional train departing after 15 minutes, and if you miss it, just get on the next one. If you make it, good for you.

I was just in Bologna last week and used the train station several times. The high speed trains arrive at an underground part of the station and the regional ones leave from the ground level tracks. You have to go up a few levels of escalators and eventually you end up in a tunnel to the ground level tracks. It's a little confusing the first time you arrive. Either way, 15 minutes is just about doable, but pretty tight, especially if you aren't familiar with the layout or have baggage to haul around. Also, trains are often delayed in Italy (high speed included) and you might want to give yourself more of a buffer if possible.
Where are you connecting to? As mentioned, some trains have "east" and "west" tracks, some just a regular track number. Regional trains to areas interesting to tourists (Ravenna, Ferrara, Venice) seemed to leave primarily from the "main" station with regular track numbers and were therefore easier to find. The east/west tracks seemed to be mostly local small trains and we never used them.
I recommend using the Viaggia Treno site http://www.viaggiatreno.it/viaggiatrenonew/index.jsp - gives real-time updates on train status, delays, track numbers, etc. You can see arrivals/departures by station or do journey planning. Was very helpful when we were using the trains in Italy.

Here you can find a 3D map about the Bologna train station: https://help.g2rail.com/it/stations/bologna-centrale . On the map the West station is on the right (Milan direction), while the East station on the left (Florence direction).
15 minutes is enough to reach next train if you know the station and know how to move, but if it's the first time is very tight. My suggestion is to use the websites given above to plan accurately the route and maybe check before the arrival from where the train is leaving.
One trick: all trains start/end in Bologna usually are on the two sides stations (for example: a train Bologna-Piacenza starts from West station; a train Bologna-Rimini starts from East station). All trains passing through Bologna stop in the Central station (for example a train Piacenza-Rimini). If you find the details about your train you just know where to go.

Dario, I dont have the train numbers. I am still in the planning
stages.

In that case, don't try to self-connect. Just buy a ticket from A to B. You don't have to buy individual tickets for every train.

We’re connecting to Ravenna. I’m thinking of buying a ticket from Rome Termini to Bologna and then when we get to Bologna, buy a ticket to Ravenna like many have suggested. Is there a difference in taking the Trenitalia or the Italo trains? I think there both high speed trains? Besides the Italo website I’ve found Trenitialias website and italiarail.com that offer the same tickets. Is one better than the other?

How do you validate a ticket? I’ve read this is a thing in Italy.

We bought our tickets from Bologna-Ravenna at the station, as there was no price advantage to buying them ahead of time. There are tons of automated ticket machines (in English) that are easy to use. You can buy one-way or roundtrip - we just bought our return ticket in Ravenna so as not to have more pieces of paper to keep track of.
Yes, we had to validate our regional train tickets - also very easy. The validation machines are around the station and at the entrance to the tracks. This post has a photo of the validation machines https://www.marthasitaly.com/articles/11/italy-travel-tip-validate-your-train-ticket
Never used the Italo trains, so can't give input there.

We’re connecting to Ravenna. I’m thinking of buying a ticket from Rome
Termini to Bologna and then when we get to Bologna, buy a ticket to
Ravenna like many have suggested.

Why not just buy a ticket from Rome to Ravenna instead? That sounds a lot easier to me.

Is there a difference in taking the Trenitalia or the Italo trains? I
think there both high speed trains?

Trenitalia is the big state owned railway company that operate high speed trains, local trains and everything in between. Italo is a private operator that only operate high speed trains.

and then when we get to Bologna, buy a ticket to Ravenna

Why? What would the benefit be? None, imho. Cons:

1. If the high speed train is severely delayed because of Trenitalia you won't have a protected connection (same if you travel with Italo and you are late because of them)
2. You'll have 2 more thingS to think of in a labyrinthine station: getting the 2nd ticket and validate it before boarding the Regional to Ravenna.

Sometimes 15 minutes is not enough time to transfer especially if you are traveling with luggage. However, if you are traveling on Regional trains, you can always take the next train if you miss your train.

I was in Italy a few weeks ago, I bought my tickets directly from a Trenitalia rep in Venice. She let me know we could board any regional train to the destination.

On one leg of our trip, we arrived early at the train station and we boarded a regional train with no problems.
Have fun planning and traveling .

Wait, you can freely board any Regionale train departing within the FOLLOWING 4 hours from the scheduled departure of the booked train.

Let's say that you have a ticket for the Regionale #1234 going from A and to B that departs at 3:00 pm. You can't get on a Regionale from A to B that departs at 2:55 pm. You can get on any Regionale departing between 3 pm and 7 pm.

A Trenitalia conductor in a good mood may not fine an obvious american tourist who boarded an earlier Regionale, but there are so few conductors left on Regionale trains that meeting one in a good mood is like meeting an unicorn.

I used the Trenitalia app for all of my train tickets in Italy. It's easy to use and I was even able to get a few dollars of compensation via the app when one of my trains was really late.

Getting from Bologna to Ravenna can be slow by train. Last month while in Bologna we decided instead to splurge and hire a driver who picked us up at our hotel and drove us to and from Ravenna. We contracted with him for a four hour stay in Ravenna, which worked perfectly. The Ravenna reservations put visitors on a scheduled system (twenty minutes here, 15 minutes there, etc.). We saw all the sites and also had time for a pleasant lunch before meeting our driver at the appointed time and place. I recommend the driver and his ultra-clean car: Mario Piccone (+39 348 6001100) His email is [email protected]. We always used trains on our three week (wonderful!) journey, but hiring a car for this particular day trip gave us a very pleasant day in Ravenna.

I don't remember any trouble getting there by train from Bologna. 6 past every hour, train (Regionale) takes only 1:10 and only costs 7.35€.

I can't imagine a driver would be much faster and certainly a driver would be much more costly...

Ravenna is easy to walk around. I don't walk fast and was able to see all the mosaics

As Nigel mentions, there is a cheap regional train that leaves every hour and only takes a little over 1hr to reach Ravenna, same as driving. Our trip for 2 cost less than 30 Euros roundtrip - you don't say how much the driver cost, but I can't imagine it is competitive with that? The only reason I could see for using a driver would be a train strike or similar issue.
From the train station in Ravenna, it's a short, entirely flat walk into the town center and all the sites are easily reachable by foot.
Also, when I was there last week, you did not need timed reservations to enter any of the sites. There were hardly any other tourists there, so they may have given up on that system for now. What happens next May, who knows...?

The top benefit to do Bologna - Ravenna by car is if your starting/arrival points are far from the train station and you can do at any time you want. Somebodies prefer it. But I believe that hardly you can find a driver with a lower cost of 50€ for each route Bologna to Ravenna. So a total cost that is 6/7 times higher than by train. Even the travel time isn't very different.
In general in Italy when you move between cities the train is a much better solution.

Even if I agree with Nigel and hopper18 about costs and reservations, a driver could be useful to visit in a few hours all the mosaics in Ravenna. Including those in Classe, where people with reduced mobility could go only by bus.

This way you see nothing of Ravenna itself, it's Not my way of travelling, but it makes some sense.