New to electrical - What do I need to get my lights worknig?

[TwoFiftyShifter]

So I've had my 64 GMC for 6 months now, it's my first truck, but haven't had the desire to really dig into it. I have that now. I have little experience with electrical stuff, so if someone couls tell me what I need to buy to get into this, It would be great. My buddy is a little better (but still a dumb kid, lol) and hes coming over tuesday to work on it with me. Heres a rundown.

I replaced all the fuses in the fusebox.
What works:
Turn signals up front, parking lights, dash lights and indicators, and the aftermarket radio. The horn also works.

I use a test light and the following things have no power: Wipers, no power at the fuse box with a new fuse. Maybe the clamps on the fuse box are corroded? Dome light - No power at all at the dome light, just on the fuse box. No clue about that thing. Headlights - Power at the fuse box, no power at the firewall where they plug in. Brake lights/Tallights - There is only a cluster of wires going to the back of the truck and at the end of it theres a 3 prong plug. No power at this plug.

Not sure if you guys can help me, but is there like a wiring old cars for dummies book? Will I have to buy an expensive wiring harness? I'm pretty low on cash. Thanks for any and all help. The old thing runs drives and stops, I'd be willing to bet that if I get all the lights working I can get plates on it and drive it this fall.