You can get all the info you need right here, do a search for all post by Whittler (he builds a solid crankbait).
topwaters are not the easiest baits to build, you might want to start will a shallow running flat sided bait to get your feet wet. Balsa wood is the easiest wood to carve and shape.
The finish on my baits and whittler's is not from the paint, it's clear topcoat. I use water based paint and the topcoat makes it water proof.
get you some 1/2 thick balsa, 20gage stainless steel wire, a good carving knife, 150 and 400 grit sandpaper.
when you have your supplies, I can help thru the rest.
welcome to the darkside