Well, RB is different than BiaB, and while Noel is showing how to do it in a way similar to BiaB, I'd do it differently in RB.
In RB, in the main Tracks view place the cursor where you want to make a change.
Right click in the track data area of the track and select Insert Volume Change.
I'll post screen shots in a minute.
If I recall this works with both MIDI and Audio tracks, which is one reason I always liked this method in RB.
You can Undo, or manually change the volume change data, or redo over it.
There is also the 'Fill' option which can make changes smoother (fade out a track in this section, and back in at this section.. instead of sudden muting methods).
In the images below I set the cursor to end of Bar 8 (roughly)
Right-clicked and selected Insert Volume change
The pop up let me select a new volume (I chose 4, but zero would be muted)
The last image shows the resulting volume change command at the end of bar 8 (4), which changes the original volume command set at bar 1 (100).
Simply insert another at the bar you want it to stop muting (back to 100).
/note- 127 is max, and 0 is mute in volume settings