If you are new to Mastodon, or, like me, not so totally new anymore but still puzzling how this all works, read Noëlle Anthony's awesome Guide to Mastodon: https://github.com/joyeusenoelle/GuideToMastodon/
Tools are only as good as their documentation, user guides and communities. Thank you @noelle , you made Mastodon an even better tool for me (and I suppose a lot of other people too) now.
We also provide a guide on security and privacy settings of Mastodon: https://infosec-handbook.eu/blog/mastodon-security/
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!