As crazylocha says, you really do need a manual for your tractor.
The rotary pumps are easy.
First of all, make a note of which line the pump is timed to. See photo below. Remove the injector and inlet/outlet lines from the pump. Remove the small cover on the front of the main timing cover. Remove 3 screws that hold the gear onto the pump shaft. The gear will be held captive by the timing cover so it can not skip time. And the gear is indexed to the pump shaft so it will only go on one way.
Remove 3 bolts that hold the body of the pump to the block plate and the pump can be removed.
Replace in reverse order.