Wireing my head unit in an s10,now lights wont work..WTF!!!!

I recently just put a head unit in my sdime and had no wire harness so, I thought I could wire it manualy and be alright but now all of my dash lights and parking lights wont work so How Do I Wire it correctly without a harness I know it could be done cause oddly enough I done it before and I dont remember how to do it can you help me???? J.C