To mount the wheels:
Screw on two black axle supports (one on each side, and on the outside of the beam). See the picture for placement. Then screw on the motor facing outward, with a spacer between it and the beam. There should be a space between the green axle holder and the beam. Now slide an axle in, but put a stop-collar around the axle between the motor and the beam. Next slide a spacer on the axle (on the outside of the beam), and the a wheel after that. Finally slide another stop-collar on after the wheel, and then tighten the collars up. The two collars will ensure that the wheel and axle do not come out of the motor.
To mount the front roller:
Screw on one black axle support (on the inside of the beam). See the picture for placement. Now place another support on the opposite side and instead of connecting it with a screw and nut, place a screw through the support and screw in into the motor. So the motor should now be connected to the frame with the green axle support on the very end. Next take the paint roller and insert the black grommets (they should have spikes around the outside and a square hole in the middle) into either end of the paint roller. Then slide a long axle (the 12 inch) through the frame, through the grommets, and finally into the motor. Use stop-collars to hole the roller in place.