he asked for a simple diagram, so the stock diagram isn't "simple" compared to the bare bones chopper ones. i used that chopper one posted along with two very similar to these, and it yielded good results. if you want turn sigs, you'll need to incorporate that part of the stock diagram into your build, as i don't know of a simpler way... make sure you have GOOD GROUNDS and adequate and quality wire, and you'll avoid a lot of problems. also, relay your headlight for sure, and horn if you want. makes it brights and last longer and your horn will be louder w/ constant pitch.
the "peace sign" in the center is just your key switch. it takes a constant hot to it, so it'll allow power to flow to the lights and horn, and then it allows it to flow to the starter as well on another pole. make sure you also have a good fuse box, i'm going to use modern blade styles that have the little lights on them to show you if they're blown.