No worries my friend, we all have to start somewhere! I found the following posts/forums extremely helpful:
MotoredBikes.com: Motorized Bicycle Forum - View Single Post - Tips I've learned from many builds-great newbie read.
Classic Instructions for Building and Repairing Motorized Bicycle Engine Kits - Motorized Bicycle: Engine Kit Forum
I find as you tinker and continue to build more questions arise. Most everything you need to know about working on these engines are in these forums. Personally, I did most everything listed in that first thread that I had the tools and capability to do. If you're using a cruiser bike and need a custom front mount I can't say enough about Al.Fisherman. He made me a custom mount for $20 and it works great.
For my motorized bicycle specific parts, I like www.sickbikeparts.com
. Everything else I get at my local autozone or hardware store. I know it's exciting and you just want to ride, same thing happened to me, I'm glad I took my time though. If you're going to do it right, might as well start from the beginning..if you do your HT will thank you in the long run.