It’s really hard with small, starting instances.

Basically, the only content that gets federated to you is content produced by someone that a person on your instance follows. And once it federates to you, it becomes searchable and viewable to other members on your instance. Which means that the more people you have, the more content gets federated too you, and the easier it is for your users to find new content.

And new users that no one on your instance follows at all won’t appear to any of your users in searches etc, which is where “boosting” a post comes in. If I post a photo, and no one on your instance follows me, none of your users will see it. But if someone that they do follow, follows me and likes my photo, they “boost” it, and then it appears in the timelines of people that follow them. And then once a single person on your instance starts following me, my future content will start federating to you.

Which means that as an admin, the best thing you can do is start up a seed account, and just follow lots and lots of people. Follow random people. Follow anyone and everyone, just so you get a critical mass of content sliding to your instance.

This is a problem that all fediverse platforms suffer from. The initial hump to get good visibility of federated content is a challenge. Once you cross it, you’re fine, but to cross it, you either need to be patient and give it time, or you need to artificially kickstart it