James, should look just like this or very similar. If you notice on the very front a knob that goes into a trap door. You loosen that up, door swings open on a pin. You put motor shaft into that, close door and screw in bolt with knob. This will also be used to adjust height of motor in bracket when deployed into the water.
Bow Mount Trolling Motor Bracket Arm & Deck Bracket easy quick release lift | eBay