Hmm....
They typically come with a remote. Each button corresponds to a different "view".
For the VA lines, they are typically grouped so that similar-sized lines appear together so that you don't have a button (or "view) for each of 20/20, 20/25, 20/30, 20/40 etc etc., you'll have one "view" with 20/25/30, one with 40/50/60, one with 70/80/100, etc.
Other stuff you can do is put R/G over top the "view", as well as isolating lines and letters.
You have to look at the remote at least once, and play with it a bit to get the hang of it.
Try googling or going to a manufacturer's website to find a picture of a typical remote.