Starter help for 1969 c10

[btraudt]

Hi - I'm an extreme novice when it comes to engines but I have a 1969 C10 and the wiring is pretty messed up. The engine is turning over but can't seem to get the engine started. The purple wire goes to the ignition, the large cable goes to the battery. There is another male end that I think should be connected somewhere but can't figure it out. I've attached pictures of the starter and some of the other components