Recording a Second Track

Sorry if this is a repost - I saw something similar, but didn’t quite understand how it applies.

I’ve recorded a drums in Track 1.
I want to now record guitar in Track 2, but without the result of Track 2 having both the drums and guitar. I only want to monitor Track 1 and listen to it while recording Track 2. I want Track 1 to only be drums, and Track 2 to be only guitar.

On another post, it mentioned toggling the 2TK to Mix Button (I have an Alesis Firewire MultiMix 8 Mixer). This is already pressed down. The 2TK to CTRL Room button is not pressed down, but the Mix to CTRL Room button is pressed down.

To only listen to Track 1 while recording Track 2, is the solution with the mixer, Cubase, or both?

Thanks in advance for any help!!

mixer.

Specifically, if you did read the other post, it would suggest that the 2TK to mix button NOT be down.