Take the engine out and line up the wheel on the starter box so it is centered in the opening for the flywheel.
Now install the positioning pegs on the starter box so your car will stay in place.
Make sure the starter motor engages before it comes through the chassis opening.... there is a screw that will adjust this- located near the "contact plate" inside the starter box.
Make sure the starter wheel turns toward the front of the car so that the engine will start in the right direction.
Re-install your engine and give it a go