Help me reprogram my garage door opener

I have a liftmaster garage door opener, Model 1145LM, serial number 0422101232. I wish to reprogram a liftmaster remote, model 61LM, to work it. I have two separate garage doors, each with Liftmaster openers. Garage A has two working remotes, garage B has no remotes at all. They just seemed to have vanished over time. I wish to reprogram one of A’s remotes to work with B. I no longer have the manual. Opening one of the remotes shows a set of 9 switches, each with three positions. The website says to set the matching set of switches in the opener itself to the same position and viola. Unfortunately, dismantling the opener itself discloses no similar switches. The wall switch is only a doorbell type thing, so it’s not like the old Sears models where the switches were on the wall part. Does anyone know where the switches are in the opener itself?

Here

Thanks, I think I see what my problem was. Although I was earlier at a similar website, I think I misunderstood the instructions. I now get the impression that what I have to do is change the jumpers on the remote, then let the opener learn it by pressing the button on the back of it. Before, I was searching for similar jumpers in the opening unit itself.

I hope somebody can answer this: I have a door opener with two remotes. one stopped working-and I followed the procedure to re-program the system. Now the remote control that DIDN’T use to work works-the other one doesn’t! Anybody know what i’m doing wrong?