@DavidBond you open another instance, go to user directory and follow people you like. It also makes their post appear on federated timeline for everyone on your instance. There are bots that do this to randomly populate the federated timeline for you, cause we humans can't handle anything but a linear list.

Some clients allow you to follow the local time-line of another instance, I prefer that method of discovery, but it's not proper protocol, and they say if you keep doing it the fediverse will go blind.