facing the car there should be a screw at the top and one on either left or right side of each headlight
they are spring loaded so when you crank them in our out they will stay put.
i usually park about 6 feet from the garage door and put a piece of masking tape 36" from the ground up
on each side and set the lowbeam headlights to that, then hit the highbeams and level those with the lowbeams.
depending on condition you may have to remove headlight rings and use PB blaster or some other rust remover
before attemtping so they dont snap.