If you are unsure what IRC is then please take some time to watch the Youtube video below and there are others.
I am generally connected to :
https://freenode.net/ – Various – please see above
https://www.oftc.net/ – a few Debian related channels
http://www.spotchat.org/ – Linuxmint-help
If on any of the above servers you are expected behave as per that communities guidelines. With respect to Debian channels on OFTC there is also the Debian Code of Conduct.