I am new and disabled and would like to meet new friends. I am a complete newbie and I have Ubuntu 12.04 LTS. Any help would be appreciated.
It may depend on the chat protocol. Click Room -> Join.. -> the + sign next to Room list. Depending on the chat protocol you're using to chat with it may let you click on it or it may not. All I have are Facebook and Gmail setup in Empathy and neither of them work with this option. Perhaps a standard Jabber server will work. As for IRC not so much.
For IRC click Edit -> Account -> the + button to add a new account -> Jabber and change it to IRC, you can do freenode or you can click it and change to another IRC network, put anything you want in the IRC nickname box and click login. One issue though, there's no way (that I know of) to list all channels (rooms) of a IRC network in Empathy. You can join channels but you have to all ready know their names to enter them manually.
One option, if you want to chat with random people on IRC networks, is to use something like Xchat which you can find in the repo. Depending on what you want to talk about will depend on the nature of the IRC network and the nature of the channels in that network. Chatting on IRC is the only way I know of if you want to find random people to talk to and Empathy isn't something I would use for that.