Actually its very simple.
the prop shaft is either already open for the ham standard prop or it's plugged for the Curtis electric. The parts book shows the lock plate,screws, round locking nut and alum spacer that close off the oil passages.
The 3 screws and plate are easy to remove. the locking nut takes a hex tool and 200 foot/pounds or more Tq to loosen. Then the aluminum spacer comes out with the copper gasket. At that point you will see a steel disk with one hole in the center and a ring of small holes at the edge. Stop at this point. You are now ready to install the propeller, the transfer tube and the dome. follow the manual as steps and tightening are rather important.
The prop gov mounts same as the electric one. However, the governors come in two rotation directions and two choices for the oil feed ( A or B). Make sure you get the one for the P-40 aircraft. That and use the rubber gasket with the wire screen in it.
Last is the gov drive coupling: some gov come with the spline drive as a built in part. most do not and need the drive part. They come in two lengths, about 1 1/4" and 1 3/4" . the short one is correct. the long one will damage the governor.
Once all that is done you still have to rig the control arm/cable. you want someone who has done it before to help with that.
Mike