@Daniel > If you don't have AUTO-CUE enabled and you press the CUE button, there isn't a cue point for it to return to, so it won't respond. Ensure you have set a cue point first.
Your channel trim adjusts the inbound signal to the channel; set that so the channel meters peak around the first orange LED. Then, with the channel fader all the way at the top, and the crossfader disabled or fully to that channel's side, adjust the master volume knob until the master meter LEDs are at the same level as the channel peaks.