Start off by taking the Fediverse 5-5-5 Challenge!
It's simple and you do it every day for five days (or over 7 days) and do three things every day.
1. Post five toots (new posts and/or replies)
2. Boost five toots
3. Follow five people
More details here: https://socel.net/@admin/108232703604923076
Read this toot about being a member of Socel: https://socel.net/@admin/101180139985796794
Lastly, invite friends to join by creating an invitation under Preferences > Invite People
Socel is a place for animation professionals, freelancers, independents, students, and fans to connect and grow together. Everyone in related fields such as comics, illustration, and video games is also very welcome. As an implementation of Mastodon, Socel connects you to almost two million users around the globe as part of the Federation; a network of independent social spaces communicating with each other.