Changing Trains in Frankfurt

Start heading toward the door with your bag before the train stops in Frankfurt.
Next time fly direct or buy a ticket with a longer connection if you are not familiar with a train station.

I am assuming you change trains in Frankfurt HBF, not Frankfurt airport or some other.
In that case, 13 minutes is enough, and there aren't any stairs to navigate - Frankfurt HBF is a terminus station, so you just walk to the end of the platform to the main concourse and go to the departure platform.
And if your oncoming train is late, you can take the next one if there's a next one - go to the train info point in Frankfurt to have your ticket 'endorsed' for travel on the next train.
And congratulations for not flying,

Our seat reservation says the station stop is Frankfurt(M). So is that the Terminus station referred to. We don’t think it is the Airport Station ?

Step 1: Make sure you know which station you are supposed to change train at. If your track is Fern 5 I suspect it is at the airport and not at Hbf. If it is, it should be an easy change as there are only two platforms there.

Frankfurt(M) is not a station, it is just a shorter way of writing the city's full name (Frankfurt am Main). Where did you buy the tickets? There should be the name of the station on the ticket, probably Frankfurt Hbf, Frankfurt Flughafen or Frankfurt Süd.

Bought ticket through bahn.com and the station is Frankfurt(M) Flughafen Fernbf

Research says Flughafen is German for Airport. And in reviewing we see that it is F - Airport Fernbf. So we are at the airport station obviously. And you are saying the 13 minutes should be enough time to find our connecting train and Platform. Do we just quickly get on the correct train and then find our car or do we need to look for our assigned train car number ?

Thank you

ICE 105 does not stop at Frankfurt(Main) Hbf, but it does stop at Frankfurt(Main) Flughafen Fernbahnhof, on Track Fern 5 at 11:49
ICE 27 calls at Frankfurt (Main) Flughafen Fern 5, arriving at 11:59 and departing at 12:02.
That is a 13 minute connection, so it looks like you change at Frankfurt airport. Since you arrive and depart at the same track (Fern 5), you just get off ICE 105, wait for it to depart, then ICE 27 pulls in and you board. you don't have to even move.

Thank you so much. That is a huge relief to know as the 13 minute thing was concerning. 👍

Yes, Frankfurt(M) Flughafen Fernbf is one of the stations at the airport. The one used by long distance trains. Since both trains stop at the same track, 13 minutes is a lot more than needed. Since it seems that your seats are in car 28 on both trains, you probably don't have to move more than maybe 15-20 metres on the platform. But it is usually a good thing to find the correct car before boarding, since the train can be made up of two train sets and you don't want to end up in the wrong one.