If you've never used Mastodon before.... Home tab is where only stuff you follow goes. Local tab is for all of Fosstodon. And Federated is the whole federation of instances..... so literally anything on Mastodon's main fediverse can be on there.
Spend most your time on Local to meet people and Home to curate stuff.
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.