Nostr is not a place, it is a language that a variety of apps speak and understand.

And yes you are speaking it right now :)

Your identity here is a cryptographic keypair. Maybe you get the point if you download a different Nostr app, and enter the nsec that you generated in the app you use now, into that new app to log in; see what happens :)

Remember to keep the nsec a secret.

Good luck