You need to look at Mike Fokke's boxster site. He has a great link for top replacement info.
https://sites.google.com/site/mikefocke2/mikesporscheboxsterwebpages
Of course, you don't need to replace your top but the site will show you what's involved in removing the rear seals...yes, there are two.
Be careful removing the seals...they are expensive if you rip one!
Once you get the top apart, you just need to clean off surfaces, install inner seal and glue top fabric to frame (3M adhesive).