I bought my turn signal from obsolete chevy and directions and wiring diagrahm came inside the box. The letters inside the circle are the terminals on the turn signal flasher. There should be two different circles showing different wiring diagrahms depending on the type flasher you have.Just study the diagrahm and use wire nuts until you get it right. When it's right them crimp or solder . I had to build my harness from scratch one wire at a time.Take your time , you can do it.