As a homeowner, you should reset the opener to prevent outsiders from opening the door with a remote that's set to a Liftmaster default code. A simple procedure allows you to reset the opener for one or more remotes.
doorsill - the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway. doorstep, threshold. 1  doorway, room access, door, threshold - the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close; he stuck his head in the doorway.
Most walls include a door or window opening. Additional framing support is needed to transfer the structural weight over the opening and down to the floor. This framing is done with trimmer, king and cripple studs and a header. On the top and bottom plates, mark the center of the window/door rough opening.