Well, you bought into a heap of it...
1st, remove the trim tilt switch from the handle if you cannot reach behind to unplug it.
Then you will need to slide the control box down the gunnel usually toward the stern until you can gain access to it.
You will also need to reach in there and disconnect the two yellow with red strip wires. There should be bullet connectors on them if it was rigged properly.
You may need to unhook the cable ends from the motor and feed those back as well as you slide the box down the gunnel.
Good luck!!! Thats a pain in the rear job. The new kid at the shop gets to do those...