Just reposting this as since Elon Musk bought Twitter, there has been a big migration over to Mastodon.
Joining a new network can be daunting, especially if you don't know anyone. This is especially true with decentralised networks, such as the Fediverse.
However with the Fediverse help is at hand, in the form of Trunk. The website helps you find other users by interest, gives you their id so you can search and follow them.