To Open The Cover
Place your palms on the tailgate and squeeze the handle to the tailgate to take pressure off the latches. Turn the lock-lever clockwise to 10 o'clock and let the cover open slightly. 

Give the handle a slight push while loosely holding the pull strap. This will reduce the momentum of the cover as it opens, while allowing the lock-lever to strike the housing lid with enough force to cause it to reset.

To Close The Cover
With the tailgate up, simply pull back on the pull-strap until the cover either engages the stop positions within the tracks where you want the cover to stop, or the handle engages the tailgate lock-strip.

If closing the cover to the tailgate, make sure to pull back SMOOTHLY with both hands on the handle so as to make sure both latches engage the tailgate lock-strip simultaneously.

To secure the contents of the bed, make sure the tailgate is up before closing the cover. If you wish to close the cover with the tailgate down, make sure the lock lever is turned to the 7 o'clock ("latched") position, and then gently pull the cover back to the last stop position.

Secure The Pull-Strap
If you intend to drive with your cover even partially open, make sure the pull-strap is securely fastened at all times.  Failure to do so may result in damage to your truck, your ROLL-N-LOCK® retractable cover, or both.