Starting car from starter relay

So I turn the ignition switch on and then go under the hood where I put the alligator clip to the big battery stud and then would take the other end of the jumper wire to the black wire with the screw and square post. When I accidiently grounded the one end of the alligator clip it was only connected to the big battery stud and the other end fell down to the header sparking for a moment. Thanks for help. Jayson