I have a Genie Bluemax garage door opener, and I cant find the "learn code" on.?

I have a Genie Bluemax garage door opener, and I cant find the "learn code" on. Need to program new remote? I tried programing new remotes and can not find the "learn code" on. I do not have the manual or exact model #. I think the year is a 1993. Someone said before 1994 they didn't have learn code ons. If this is true how can I program these remotes? I've search all over the web for a answer, but all instructions say to use this "learn code on" which it doesnt have or its hidden really well.