is the rear window and the bottom white piece separate? from the side sail panels that velcro onto the rear window? (all of mine were) if so
make sure the front of the sail panel is in the correct position fore and aft. it looks like it's a bit short to the quarter window. then you can pull diagonally against the wrinkles in the sail panel (I'd fix that left side wrinkle in the window portion first though it is folded in pretty bad), spray some contact cement to stick it straight and put tack strip back on
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