Create an account at PwOSS - Riot and follow the instructions.
You automatically join the PwOSS main room (channel).
Join the communities:
In the left sidebar you will see your joined communities (organizations).
You see all PwOSS - Organizations, e.g. the main devices (desktop, server and mobile). And the main organization of PwOSS, which includes all the chat around PwOSS in gernerall.
PwOSS - Organization overview.
Desktop - Organization overview.
Server - Organization overview.
Mobile - Organization overview.
To create your own room isn't hard at all.
Just click the
+ button on your left sidebar (where ROOMS is listed) and follow the instructions.
Now you can invite other people.