I have managed to source a replacement headlight to replace my cracked one.

Obviously changing involves disconnecting some wires and a few screws. But i was wondering if there was anything else that needs to set up? level? how?

Best thing to do is park the car somewhere (infront og your garage doors - a few feet away), turn on your current head lamps, note where the beams bright points (for want of a better word) hit the door. Remove the old unit, fit the new unit, and adjust until the bright points are approximately matched. Key things are the beam does not stray too much to the right (otherside of the road) or too high.

My MOT place normally fix my lights if they are out of adjustment FOC. This year, the light I had removed was fine, but the passenger one (which I have never moved) was wrong.... weird!