@Ivan Reese Great, thanks for adding them! π For Matrix clients, I would suggest trying Riot (
https://about.riot.im) first, as it's the reference client and most similar to Slack. (Disclaimer: I am part of the Riot core team.) There are many other clients (
https://matrix.org/clients/) as well for different platforms and UI styles, including terminal-based for those who prefer an old-school IRC-like experience.
To use a Matrix client, you will need an account on a Matrix server. It's a federated system, so you can create an account on any server. Riot will guide you through creating an account if needed. The
matrix.org server is free and open to the public, but you can also self-host your own server or use someone else's if they have open registration.
Some day (soon I hope) there will be a matrix:// URL scheme, but for now there's
https://matrix.to/#/#_slack_futureofcoding_general:matrix.org, which shows an interstitial page explaining how to reach a given room in several popular clients. It might be good to linkify the aliases on the community page to point there.