All participating instances have a bot that subscribes to participating communities from the other instances. This makes it so a community is federated over to all participating instances.
Example: You create !ask_kemmy@lemmy.com and around 70 bots from other instances then subscribe to it. Now users on those 70 other instances sees the community and subscribes themselves. The bots see this and they unsubscribe because their work is done.
All participating instances have a bot that subscribes to participating communities from the other instances. This makes it so a community is federated over to all participating instances.
Example: You create !ask_kemmy@lemmy.com and around 70 bots from other instances then subscribe to it. Now users on those 70 other instances sees the community and subscribes themselves. The bots see this and they unsubscribe because their work is done.