Find where the antenna comes out of the garage door opener motor and
look for either a learn button or a set of switches. (You may need to
remove the lens cover from the motor head). If the antenna is not
found, look for a wall-mounted external receiver with antenna. It
should also have a removable cover.
program using the learn function, push the learn button on the garage
door opener motor. An indicator light should turn on and glow steadily.
You now have 30 seconds.
Press and hold the corresponding learn button on the remote. Stop once the motor light blinks instead of remaining solid.
program a switch-type opener, again take the cover off of the motor
unit or wall mounted receiver (wherever the antenna is located). You
should see either 8, 9, or even 12 switches that may have two or three
the battery cover on your remote to locate the remote switches. For
every switch on the motor, set the remote switch to the exact same
position. Open = Off / Closed = On. This is where the pen or small
screwdriver may come in handy for moving the switches.
Close the battery cover and test the opener. If all switches match, it should work immediately.
I hope this helps.