Welcome to Bitcoin, welcome to Nostr
Nostr is a protocol, and Damus, Primal, Amethyst (and others) are apps to interact with that protocol. The sweet thing is that the underlying data - your data, your notes, your connections - are at the protocol level, so connections you make on Damus are the same ones that will exist for you on Primal or any other Nostr client .. this is the key difference between Nostr and all other centralised services like Twitter/Facebook/Instagram etc
Protocols > Platforms