Any chance you are also planning to go to Rome? In that case, I'd suggest flying into Venice and out of Rome. SO MUCH easier to deal with schedules. Getting back to VCE early in the morning is a pain but check schedules and see if it gets you there in enough time for you to check in, go through security etc etc. And expensive way would be by water taxi (you could take that both ways). Your hotel can arrange that for you.
There are a few ways to get from the airport to Venice. I found that the easiest is the bus. It takes you to a good place to get on a vaporetto. BTW, vaporetti (notice the plural) run on schedule: 'we're coming.' But they are frequent enough. Your hotel can tell you which vaporetto number and which stop to take. There are several different routes the vaporetti take - you want to get on the correct one. There are maps at each stop to help you figure out where you are and to make sure you get on the correct boat.
Welcome to the Forum! Everyone of us will be glad to answer questions and help you sort things out. When is the trip? If it is within the next year you might want to get busy. Italy is quite crowded this year. I booked my Venice apartment back in January.
I checked yesterday to see if any other apartments were available - they were a couple, just $$$ more than I paid, or usually pay. Venice is a very special place. Be prepared for a wonderful experience! And remember: you deserve this!