Well..... this old goat finally got a computer radio!!

Everything is going well except I have a question about the programable mixes, 1 and 2, on the Futaba T6XA radio. I have set up my first mix OK....... switch up is off, switch down is on.
What I don't understand is how do you put in the 2nd mix choice, ( actually I should say "select" the 2nd choice via the switch once you program #2)?? OR can you?? I guess maybe I am spacing it, but the switch only has 2 positions... off and on, so I am lost on how the 2nd choice be selected? Thanks in advance.....lownslo...
Bob