Instructions are found in the Operator's Instructions Manual.
Take the side cover off the clutch compartment.
Turn the clutch adjusting collar until the lock pin is accessible.
Pull the lock pin out and turn the collar to the right until the lock pin drops into the next hole. (to tighten)
Test the adjustment, use a slightly loose setting rather than to tight.
If there is any oil in the clutch housing, remove plug and drain.