If you ratchet your seat all the way forward, you should be able to trigger the release to fold the seat forward from the rear. Once folded forward, look in the fold, specifically on the bottom of the backrest there's 3 interlocking pieces pf plastic. Separate those and you should be able to work the upper seat cover off. Once thats off, you can make the required repairers. Tie a long string to the new loop and feed it through the hole on the seat cover, then reverse to install the cover again. Pull on the string to pop your loop back thru the hole.
Hope that helps