To change turn on/off chat alerts, open the main chat bar and click the settings cog in the top right.
Chat Sounds: When turned on, you will hear a notification ping when you get a new message.
Keep List Open: When turned on, the main chat window and list of freelancers will stay open. You can close it temporarily by clicking the blue 'chat' bar, but it will reopen when you move between pages.
Browser Notification: Turn this on if you would like a small notification window to pop out at the side of your web browser when you receive a new message. This will help you to keep up with new messages if you are viewing other websites in multiple tabs on your browser.
Available to chat: You will need to turn this on if you are using instant chat. When turned off, your messages will go into your TM inbox instead of the chat window.