Need Help with RPx400

Folks: I'm feeling stupid but I find the RPx400 user's guide very incomplete and difficult to follow.
I cannot get all the sounds to come out of the 1/4\" jack output, including the microphone and drum set.
I understand it has to do with SCOFF and SCON and SPLIT1 and SPLIT2 but I cannot get into changing the settings.
Some step-by-step help will be greatly appreciated

Control usage seems pretty fuzzy to newcomers. Is it there a better user guide, tutorial or step-by-step guide?
Thanks in advance for any good will help on this.... :oops:
Comments
Thank you for repply. But my problem basically is that I CANNOT get into changing the SC settings. As soon as I get the SC OFF display on screen it keeps stepping up into other adjustments. I can't get it to stop so to be able to change the settings. For the same reason O cannot get into the MIX adjustmentes as well.
I am doing something wrong for sure, but I cannot uderstand how to manage the \"matrix\" and make it stay where I want to change or adjust.
¿Any more detailed explanation on ho to get into the adjustment mode?
Thanks