Roof rail installation ?

Might be the wrong part. I would think the factory installed it from the corners first and let the sheet metal screw at ends land where they may.
Also, doesn't it pretty much lock itself in place so thet little or no glue is required ? I removed that weatherstrip from my conv. top frame and though it is cut into several small sections I found very little glue residue.
I'm guessing there were no instruction sincluded.
Best wishes for better days