Get separate sound in Audacity with Yamaha MG10XU mixer

I could not find a good guide to separate input singing or input music in Audacity with my Yamaha MG10XU mixer. This will work with Cubase/Reaper as well. Probably will work with any mixer and DAW.
Excuse my language. I´m Swedish :-)
Mixer, DAW, Audacity, Yamaha MG10XU