You have two large terminals on either end. One goes to the battery + terminal. The other goes to the starter. Use a jumper cable or a heavy wire to touch one to the other. Your car will turn over if the starter is good. If you get sparks and your car does not turn over your starter or starter cable is bad. To test the relay remove the wire that's on the small left side terminal in the front. Connect a wire to the battery + terminal and touch the terminal on the relay. If the relay doesn't click and the car doesn't turn over the relay is bad.