Thread the nut s facing the door clockwise until it meets the bracket then release the chain.
How to attach a garage door arm to the chain.
On the chain there is a device called the trolley.
Pull out the cotter bolt with the pliers.
Attach the bracket that connects the arm to the door then attach the arm itself.
Using pliers remove the cotter pin from the cotter bolt that attaches the upper end of the door arm to the carriage.
Swivel the arm down and allow it to.
This is where the opener arm attaches the opener to the door.
There is a threaded eye bolt that can be adjusted to get enough slack to attach the chain.
Pull the chain toward the garage door and hold it in position.
Press down on the chain with your finger.
Attach the bracket that connects the arm the door is opened by one arm that raises it as the carriage travels along the tube.