There are 3 ways to get from the airport to your hotel or apt. in Venice itself. The 1st is a water taxi and it is the most expensive. Probably 125 Euros for the boat. But if you can join up with another couple or two it might be worth the cost. Another possibility is a shared water taxi that will cost a little less depending on the number of people in your party. Only you can decide.
The 2nd and next least expensive is the Alilaguna boat. It will cost about 20 Euros per person. It takes longer, you do have to "check" you baggage so you don't have control of it the entire time, and you probably will not be able to get a "non stop" line to the area of your hotel or apt.
The 3rd and least expensive is a combination bus and vaporetto (vap.). It takes a bit longer, but that is what we do because we travel very light with just one carry on apiece. There are two bus lines that serve the airport. One is ATVO and is NOT affiliated with the vap. system. The other is ACTV and IS affiliated with the vap. system. At the airport you can get a vap. pass for various periods from 24 to 72 (or more?) hours. You can have a one way or two way bus fare added to the vap. pass. There is a good site maintained by the ACTV system that has current prices and etc.. Don't remember the url so just Google it.
If you decide on option # 3, take the # 5 ACTC bus from the airport to Piazzale Roma. Be sure and validate the vap. pass on the bus. Do not wait until you get on the vap. Also, validate the pass each time you use the vap. Then take to the vap. to the stop closest to your hotel or apt. The # 1 vap. is the slow boat as it stops at every stop and the # 2 is faster as it only stops at selected stops. We've done option # 3 many times. Easy Peasy and cheap to boot.
There is a site called veniceforvisitors.com that has a lot of good info. that you might want to check out .
Once you know exactly where you will be staying, we can give you more detailed information.
The link you provided is not a link to Piazzale Roma people are referring to.