Ok cool. Damus will search for users by npub or by Nostr address when you paste either into the search field, and it will automatically show the profile (screenshots below). The hashtag search appears while you’re typing, and you can tap on it if you want.

Which Nostr app are you using? UI is different for each, but typically if you visit someone’s profile there is a “follow” button. Follows are stored in your contact list, which is stored on your relays. Everything you do on nostr is stored on your relays.

It's kind of bad. I don't like it.