Decked Builder Remastered is in TestFlight beta. Invites go out by email — there’s no public link — so give us the email where you’d like to receive your TestFlight invite and we’ll review your request. Once you’re approved, Apple sends a TestFlight invitation to that address; install TestFlight, accept, and you’re in.
Any inbox you can check works — including an iCloud Hide My Email address if you’d rather not share your main one.