If your npub is the only one on the allow list, it will only accept your notes. Theoretically, those notes should be served to others that follow your npub. Not all clients request notes in the same fashion, so some followers may need to explicitly connect to your relay in order to view the notes hosted there.
As far as you viewing other people's content on it, you would need to add anyone who's notes you would like to host to the allow list & ask them to write/outbox to it.
There are fancier ways of pulling in content, but explaining them goes beyond my capabilities 😅