Levers and some handle grips are either right handed or left handed depending on the orientation in which the door opens and the side the hinges are located.
Determining handing for door hardware is a different than determining handing for carpentry (ordering and hanging doors). If you follow the standard carpentry rules for handing door hardware, instead of following the diagram below, there is good chance you may end up with a lock that is handed incorrectly.
Please refer to the video or diagram below:
Above Video courtesy of