In your example just select track 4 to record on, make it a mono track, and record.
If you have all the inputs selected in the drivers area RB will do the rest for you automagically. It stacks each one on the next available blank track. You don't need to make any yellow tracks and it won't help if you do. If you want them in a different order you have to move them around afterwards.
Make your sound your own!