Assemble the pieces of the pull-up according to the included instructions, if it did not come assembled.
Screw the mounting brackets on the top of the door frame, on the back of the doorway. The mounting brackets should be roughly 13.75 inches apart, though you should consult the included instructions for the exact measurements. The mounting brackets help hold the pull-up bar in place.
Hook the back of the pull-up bar into the mounting brackets. The front of the pull-bar up will rest against the door frame, on the front of the doorway. Pull on the pull-up bar a few times to ensure it is secured in place before attempting to work out on the bar.