DJM-T1 signal from PC is assigned as channel 1. How switch to master ?

Hi !

I've got problem with mixer djm-t1. When I connect it by usb he automatically  assign signal as channel 1. How switch it to master, not connected with any channel ? I know there is a possibility to connect it by aux, but there must be a way to change audio output settings. I know i mac there is "in options", but i am using a windows 7. I can't believe that is impossible in windows... 

Sorry, becouse my languge can be a little bit primitive, but i haven't been using language for 6 years.