A garage door opener install moves in a set order. The track and the header come before the arm, the limits come before the force, and the safety test comes before anyone uses the door. Keep that order in mind and you will know where to stand and what to check.
Before the carton comes out
Check the ceiling clearance above the door, the space at the header, the outlet position, and the spot where the wall button will sit, away from children and moving parts. Note the door's weight and type. Ask the installer to confirm the door's springs and balance are sound, because the opener depends on them. Confirm that the header bracket can be fixed to framing rather than only to drywall.
The hang
The rail is mounted to the header, the trolley is fitted, and the arm is connected to the door's top bracket. Watch the arm move the door through its travel. It should move smoothly without binding, and the door should stay square in the opening.
Limits and force
Set the open and closed limits so the door stops where it should. Then set the force. This is the step where the opener learns how much resistance means an obstacle. Do not skip it, and do not accept a setup that has not been tested.
Sensors and the reverse test
Mount the photo sensors near the floor on each side of the opening, aligned with each other and wired to the opener. Test the beam by breaking it while the door closes. The door should reverse. Test the force reverse by setting a board on the floor under the closing door. The door should reverse on contact. If it does not reverse in either test, stop and have the installer come back before the door is used.
Manual release and hand-over
Show the release cord, pull it with the power off, and confirm the door can be lifted by hand. Program the remotes and the keypad, and record the settings you chose. Get the manual, and record the model and serial number in your proof folder. Ask the installer to walk you through the wall button and the light.
Check before you sign
Ask whether the reverse test was run with the board, whether the limits and the force were set on site, and whether the header bracket is fixed to framing. For the unit's service life, see Garage Door Opener: typical service life and when to plan.