Hello amity, tyty,

When you sign in to PC, just above where it says “Welcome, amity”, there is a grey bar with some menu options.

One of these options is Chat. The number behind the text shows how many people are in chat at that moment. If you click on Chat, you will see different options. You only need to select a room to enter the chat.

If you would like to see who are in chat, you can choose the last option of this menu. Just play around a bit with the options...

For further info: a member of PC has prepared an excellent tutorial about how to use chat:
http://forums.psychcentral.com/showthread.php?t=178220

Good luck!
John