Ducati Monster 796 Workshop Manual page 638

Flywheel - alternator
Lubricate the race (P) of the driven gear (20) with engine oil.
Install the driven gear (20) on the starter clutch, ensuring it is properly seated.
Note
To facilitate the introduction operation, turn the driven gear in the direction indicated by the "green" arrow.
Check that the driven gear can rotate freely in the direction of the green arrow but not in the direction of the red arrow.
If either of these two conditions is not met, this means that the starter clutch has not been installed correctly.