So, you've joined Fosstodon and are wondering, "now, how does this work?"
One thing that sets Fosstodon apart from traditional social media outlets (and some other instances) is the community's willingness to help and offer valuable feedback. This is especially true with new members.
This may help shed some light
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.