This is a quick guide for those people who have heard of #xmpp but have never used it. Using XMPP is like using most other chat services.
This guide just gives a few suggestions on xmpp servers to register an account and a few popular clients for Linux.
Or you might even consider starting your own #xmpp group chat.
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.