Newbie question for all you pro's!!!!!

Ok super simple i know but need a quick hand setting up my mic>>How do i route correctly??? Have signal to cubase just not through my channel. Any ideas??? Also cubase plays through my monitors but as soon as i change my motu 4pre to phones no signal through cubase> itunes playback through phones fine. Realise this is basic shit but please tell me what im missing…
Cheers stix