Recording Multi Instruments On Several Tracks

Two questions. How then can I record the two tracks? Assuming I have drums on channel 1 and keys on channel 2 on the mixer, and I want to record them simultaneously but differently on tracks 1 and 2 respectively in Cubase, how does that work? I tried it without success. That’s why I had to come here.

  1. How can I increase the number of tracks so I can record more instruments at once?

Thanks.