I want to record more than one audio input, but I'm unable to find the option to select an input channel for a track. I can't just record from input 1, that implies only one audio input is accessible. Please help
@Scott-Hasler You can open the recording options by clicking on the gear icon next to the record button. There you can change the input. In case your interface has mono inputs (with is often the case) just set the recording mode to mono.
It is not possible to record multiple inputs at once in Music Maker. It is deliberately limited in features. You need to get another DAW like Samplitude Music Studio or from another developer of your choice.