If you're willing to buy the clam clamps (which are awesome), then the pocket screws are not needed. I do my pre-assemblies with one domino using the smallest setting on the tool. The location is determined by putting the pins on the long point of the miters. Then I put the joint together with the clam clamps and let it dry for about an hour before installing. They come out perfect every time. Only time I use pocket screws along with dominos is when I can't afford to wait for the glue to set-up. If you have enough pre-assemblies to do, then you'll have plenty of time for them to set up. Get yourself some of that molding glue that Titebond sells (sorry, always forget the actual name of it). That stuff is better than Titebond I,II, or III, for most trim applications. Its thicker and it sets up faster. It has a pretty decent initial tack too.
Its really very straight forward, and you won't need many tips, if any, once you get started. Just do a few trial runs in scrap first so you get the hang of the domino.
I strongly recommend ditching the pocket screws and picking up some clam clamps. The Collins clamps aren't bad either, but I prefer the Clams.