I am trying to set up my Mamajamba for the first time. I can not figure out the removable doors. On one edge of the door there are three attachment points. I understand the two corners but can not figure out where to attach the middle point with the shock cord. Does any one have a picture or a good talk through? I know once I see it it will be obvious. The video on the warbonnet web site shows doors with snaps down the edge. The doors I have do not have the snaps.