Armaclad Classic with Decorative Scroll Storm Door

The Armaclad storm door in the photo I've uploaded does not open. The handle moves up and down. The bolt seems decoupled from the handle mechanism. The small lock in the picture is not used, i.e., door is not locked. 
Where do I find the part number given the circumstance or are you able to discern the replacement part needed for this storm door? Thank you for your help!