tagging onto Bob's answer...

As you'd know, each bar on the BIAB chordsheet consists of two cells. So to get a C chord to play the whole bar and to add a shot on beat 2, the chord entry that needs to be typed in is...

First cell in bar: C,C..
Second cell in bar C

Note: The first cell covers beats 1 and 2 and the second cell covers beats 3 and 4. It's necessary to tell beat 3 that you are setting the chords back to normal after the shot on beat 2.

The song will need regenerating after the above chords have been entered.

MY SONGS...
Audiophile BIAB 2025