In RB, go to Options - Preferences -Audio Tab and click the Drivers button.
This should reveal all the available inputs for the selected device.
Highlight the ones you want to record.

Save/close out of Options
Select a Track in RB, make it a MONO Audio track.
Record .. RB will record all inputs and put each one on the next available blank track ..
If 8 inputs are selected you should end up with 8 MONO audio tracks with each input on its own track


I do not work here, but the benefits are still awesome
Make your sound your own!