Need Help on Receiver Board to Add New Remote

Hi All - Hoping for some help - I recently purchased a auto gate opener that has a garage door receiver board.  The board has part number 14LG598 (pictured below). I can't find any info online and am hoping someone is familiar with the process to pair a new remote.  I assume it is by using the S1 PROGRAM button, but wanted to make sure.

Thanks for any help in advance

That looks like a Liftmaster 312HM radio receiver. If you look on the back of the silver cover of the receiver you should see the model #. Do a Google search for the Liftmaster 312HM to find instructions.