New Spider 115 cover (Bj. 86)

Hello all, the cover of my Spider (bj. 86) is still original. Unfortunately, it is now so slowly tearing out on one or other outer edge. Also a crack between the rear window and the cover material has formed. Has someone changed the cover with his Alfa before ? can you make that yourself ? where do I get a cover ? what do you do with it when you change the cover ? (screws …) Thank you very much for your help and many greetings Jörg