I got a v. cool video from Setwmac.com called “How to wire a Fender guitar” though they also do a Gibson video ) and it talked me through all the basics. If you are replacing the p/us (especially with single coils) it may be worth your wile shielding the inside cavity and back of the scratch plate whilst you are at it. Stewmac sell kits for this however when I did it I used one and a half kits on one guitar.