you just remove the flywheel and fit the flexwheel instead, remember to use the shorter auto flexwheel bolts.
if you undo the three 17mm bolts which hold the flexplate to the torque convertor (access through the starter motor hole) you can leave the torque convertor attached to the gearbox and the gearbox in the car.
to remove/install the engine will require the crank bolt to be removed, so the engine can slide off the gearbox and be lifted upwards.
leave the gearbox mounts alone, just remove the engine mount on the inner wing