Basic assumption... The chimes know what time it is...!!
From page 10 of owners manual below (MINUTES
EXAMPLE: Clock chimes at 1:10 but should chime at 1:15.
Step 1: When clock chimes at 1:10 stop the pendulum and record the time of 1:10.
Step 2: Carefully remove the small nut....
procedure is on the SAME PAGE (10).
WARRANTY INSTRUCTION MANUALS