Granted it's been a few years for me. But, you already have all the hard part of alignment done. Last time, I was able to unscrew the two screws on each side that hold the frame down to the post, then unscrew the center post. Pull everything apart and reassemble without adjusting the posts at all. It took lots of soapy water and gentle pressure with a partners help. @WOLFGANG is right, make sure the back of those screws don't hit the glass edge.
-=theron