Your tractor would be a instareverse. The two pedals on the right are for forward / reverse, the left two pedals are the brakes. Make sure both shifters are in the middle position (neutral) and start the tractor. Put the transmission in gear with the tractor at idle, the left shifter is the gear selector, and the right is the range selector. Put both shifters in the forward position, then press the pedal for the direction you wish to travel. The more you push the pedal the faster you will go.
The directional pedals on the instareverse are tied to the shuttle transmission, and the engine throttle. It first engages the gears to go the desired direction then it applies throttle the more you push causing the tractor to move faster.
to rev the engine up in neutral without having to move the hand throttle push both pedals at once.