How do I repair a surround foam for this?

Ive followed your steps on how to replace / to seperate the main soeaker from its shell but the main problem im facing was the surround foam for the speaker because mine was busted amd not work really well any more so i plan to just replace it but just doing it by my self to save time and money so i ask to this site because i know that you will also help me from this problem / situation