Within Teamwork Chat you may want to create a chat with a person or group of people you have not spoken to previously.

You can do this by selecting the add message icon as indicated below which is located within the left pane of your chat window.



You can then type your message into the message field which is located to the end of the chat window.

You will then have to '@mention' the user you would like to send the message to by typing an '@' symbol into the message field. This will then populate names who you can send the message to. If the user you want to send the message to does not appear you can type their name or chat handle immediately after the @ and they will appear.

Example: 

    "@adrian". Once you start typing "@", an autocomplete suggestion list will appear displaying a list of user avatars that hold a similar chat handle. By clicking or hitting enter/return on the correct user, the users avatar will appear within the message window. 
This will then initiate a one on one conversation with the user.

If you wish to create a room, you need to @ mention more than 2 users. If you are in a one on one chat you can add more users to the room simply by "@"mentioning or through the room settings. Through the room settings, you'll find the option to give a title to the conversation.