I hadly ever use BIAB to do this as all my work apart from initial rough mx is done in RB but this should work. Open the mixer and choose an unused utility track. right click and choose 'select midi patch.' choose GM patch 106 banjo. clcik the notation icon and choose staff roll notation mode. then enter your notes using the mouse. the manual will tell you how to edit time pitch and velocity. you don't want audio as the way to enter your notes is by midi.