If you want to run irc on your tilde account, you can use weechat which is installed and requires minimal configuration.
Start weechat on your linux shell and type the following commands:
/server add tilde irc.tilde.chat/6697 -tls
/connect tilde
If you are using weechat 3.x, the command uses -ssl instead of -tls.
This will connect you to the irc network via a secure connection. The username used is your linux account, this has to be unique, if someone else registered your name already and is online you will be called username1 or similar, then you should choose another nickname. You do that with
/nick newusername
(If you didn't choose a username that is unique in the tilde network, you had kind of bad luck.)
You now can register your username using your tilde email address as described here: intro to nicks
After you have done that, you can set the username and password in the weechat settings to automatically log in and authenticate
/set irc.server.tilde.sasl_username <username>
/set irc.server.tilde.sasl_password <password>
Or to store the password securely (which is preferred), you can use secure settings like this
/secure passphrase <passphrase>
/secure set tilde_password <password>
/set irc.server.tilde.sasl_password "${sec.data.tilde_password}"
Then the client will ask you for the passphrase when starting.
Now disconnect and connect again to get your registered nickname
/quit
run weechat again and then connect with
/connect tilde
Now you can join any channel, e.g. #helpdesk
You can set various parameters, e.g. to set your real name displayed in /whois you can use
/set irc.server.tilde.realname "My real name"
You can join multiple channels with /j #channel or start private conversations with /msg nickname and navigate between the different windows with Control-n and Control-p
To automatically connect to the tilde server on startup use
/set irc.server.tilde.autoconnect on
For more information about weechat, see the manual