Hi David, welcome to the forum.
Converting old DC-only locomotives is not difficult, but does take time. You do not need to buy a book. You'll find somehelpful resources on Youtube that will walk you through the conversion process. If you can't find any there, I may take the time to make up a video showing how it's done. Really all it involves is taking a 9-pin harness and matching the wires up to where the go (they are color-coded and the Railpro instructions has a diagram showing what goes where). Remove the factory board, solder the wires from the harness to the corresponding wires on the locomotive and you're done.
-Kevin