I just looked online, and you may need the wiring harness with the reversing solenoids, but first, you need to determine whether you have a 2 wire or 3 wire motor. I suspect that it's a 3-wire, but you need to make sure.
With a 3 wire motor, black goes to negative power, and either blue OR red goes to positive power. Direction is determined by which one is powered. DO NOT touch both to + at the same time!
With a 2 wire motor the black is only a ground strap and doesn't do anything. You connect the two colored wires to positive and negative. Swap polarity to change motor direction.
Since you don't know, I would ground the black wire, and then quickly touch the red wire to +. If the motor kicks over, then touch the blue wire to + and see if it reverses. If it does, congrats, you have a 3-wire motor.
If nothing happens when you touch either colored wire to +, disconnect the black and ground the blue wire instead. Then touch the red to + for just a second. If the motor kicks over, good. Note what direction it turns. Then reverse the leads, grounding the red and touching the blue to the + and see if the motor runs in the opposite direction reverses. If the motor works in both directions, ground the black wire and carefully try again. If it still works, you have a 2-wire motor with ground.
If only one wire works on a presumed 3-wire system, or makes really hot sparks, that is a clue. Often an old unit will have a bad motor, and it will need to be replaced. A trim motor is usually only about $65 on Ebay or Amazon brand new, but you would have to search for that.
I hope this helps. If you feel over your head, take it somewhere and let someone else do it.