I am assuming you have a commercially manufactured trailer that is wired and has brakes. If you are going to pull It with the MF 35, you need to decide how extensive a wiring job you want to do. If it never hits the road, I would consider splicing into the brake wire lead near the hitch along with a ground wire to a 2 conductor coupler. The tractor side leads would go to ground and to an inexpensive trailer controller with a manual activation sliding switch. The brake controller will have 3 leads in (ground, power, and a lead from the brake pedal switch, which you don't use) and the one output to your coupler. Most controllers have a digital readout and some type of adjustment setting. It needs to be mounted in a position that allows you easy access to "feather" as needed.
When that new tractor arrives, hopefully it will have the matching trailer plug and directions for wiring in the brake controller. If not, just transfer what you have to the new ride. Good luck, ht