Barbara, below is a link to a procedure I wrote and photographed that shows the basic steps to saving tomato seeds using the fermentation method. The procedure answers a lot of beginner's questions. When you get started saving, you might do some of the things differently, and that's okay. Everybody seems to do their seed saving slightly different.
Just remember that the primary objective is to remove the "gel" surrounding the seeds and then dry them for storage. So, check it out. If you still have specific questions after that, then ask away. That's what we do here.
Ted
http://tatianastomatobase.com/wiki/A_Beginner%E2%80%99s_Guide_To_Saving_Tomato_Seeds_ Using_Fermentation