Assemble the opener tube and power head unit.
Feed the chain and cable around the back sprocket,
down to the idler in front, and back to the traveler.
Fasten the front bracket to the garage door header
at the center of the door. The bracket height must be 2" above the door's highest
point, or the door will hit the opener tube.
Attach the front end of the tube to the front
bracket. Our's fastened with a pin and clip.
With the front secure, position the opener unit on
a ladder or temporary bracing. Open the door and center the opener and anchor it in place
to the truss chords with metal strapping. 
Close the door and connect the L-shaped bracket to
the traveler. At the height of the top rollers, attach the L-shaped bracket to the center
of the top door panel using carriage bolts.
Disable the garage door latch by removing both
strike plates. After that, plug in the opener unit.
Open the door to engage the traveler. Then open and
close the door, adjusting the control knobs as needed. The door should be able to close
firmly (not hard), but retract if it encounters an object.
Buy the 
