AC8303 How to use the lever (Part "`L"), in order to tighten the arm onto the base?

How to use the lever (Part "L"):  
 
Pull the lever to release (neutral position); position the lever, to prepare for the next half turn.
With releasing the lever and turning the lever; you actually put the lever back in gear, in order to tighten the bolt.
 
Pull/release/turn