Royz:

Position your cursor in the 2nd half of the measure.
If there is a chord on the third beat AND the fourth beat, type in the first chord, then a comma, then the 2nd chord, like this C,F

If there is NO chord on the third beat, just type in the comma and then the 2nd chord, like this ,F

BIAB allows 4 chords per bar.

Good luck!
LLOYD S