1. Set the [TO PC] slide switch to [LOOPBACK].
This setting is used to mix all of the audio from each channel together with audio from the computer, and return the mixed signal to the computer.
After adjusting the gain level so that the corresponding [PEAK] LEDs flash briefly when singing or playing the loudest, turn the [GAIN] knob back to the left a little, so that the streaming sound remains clear, even if there are peaks in the sound exceeding those when setting at first.
Press the [MONITOR MUTE] button as necessary to mute the monitors.
For example, if you want to mute your own voice, or if you can hear overlapping audio from the software you are using, it can be useful to turn [MONITOR MUTE] on so that the audio from the mixer is not being outputted to the monitors.
You can use the level knobs to adjust the amount of distortion in [AMP SIM]. To reduce the amount of distortion, turn the knob to the left for a "crunchy" sound.