The "Username" box: delete the "Username", then enter the username you wish to have
(real names are best to avoid confusion in the chat rooms, but not required),

the "******" box: delete the "******", then enter your password,

the "-@-.com" box: Delete the "-@-", then enter your email address,

Hit the "register" button. (You only need to do this once)

Then enter your username and password in the "Enter Chat Room".