Hi Gio,
I mounted the gearbox first so I had the car on all 4 wheels so I could push around and check that it actually rolled.
Engine is easy to get in with gearbox installed. Engine hoist on inlet manifold, jack under the sump. Lower down and get engine resting on jack and supported by hoist, carefully wiggle it into place. You will need to get the gearbox shaft to sit roughly in the pressure plate opening to give you slightly more room. Get it aligned horizontally, push into place. Then I installed engine mounts on engine, then chassis engine mounts, takes some wiggling and some help f