In almost all cars there are two screws located behind light. You just have to find them. One in the corners are for left/right adjustment and the one in center is for up/down.
Find them, then take a look on top black portion of your headlight. There will be arrows pointing at the direction to which you need to rotate screwdriver. It would be like this anticlockwise/clockwise for up/down.
Park your car at least 20ft away and position your light either to the wall or some other car's rear end.
In order to get the perfect adjustment, both headlight must be pointing parallel to the headlights and if you're taking some car as a frame of reference then it should be pointing above bumper and lower then taillights.
