The door was easy to assemble. The overview of door said all holes were predrilled but the top board of the door, this where the rollers attach. It was not hard to measure and drill but just took more time to do it. If you have molding around the door you also need a header board for door to hang correctly. I was under the impression you only needed a header board if you could not hit the studs, I hit all the studs and the door would not roll past the door casing until I installed the header board.