To set the combination:
Unlatch so it's in the open position.
Facing upwards,push the grey switch up towards the numbers and hold in place. Set the 3 digits to what number you want and then release the switch. Combination will now be set on to the numbers you changed it to.
Note- This will NOT fit Epsilon,Oyster,old-style F'lite (not GT) or any others that aren't F'lite GT or Aeris series.