Click the "Club Management" tab and then click "Roster Builder"
Select the event that you want to build rosters for.
Note: On the right hand side, you will see the teams from your that are registered for this event.
For each team that is registered in the event from your club, you can submit any roster that has been created for the particular team. In the "Clone Roster From" dropdown, select the roster that you want to submit to the event. Then Click "Submit".
*Players can be automatically approved or reset to a pending status depending on the league's settings