Direct messages are pretty straightforward. They're a way to communicate 1-on-1 with another member. In general, try to keep as much communication in public and private rooms as possible. That way you can maximize the benefits of team transparency. But, when you do need to send a direct message, here are a few things to know:
Click the Direct Messages header or the + symbol to open a list of available direct message conversations. Type a member's name to search through a list of all users in the system.
The red badge will always display the count of unread messages you have.
If you want to hide the conversation, mouse over the conversation and click the — symbol. Since you'll always receive a notification if someone sends you a direct message, you can't "leave" these chat rooms the way you can a public or private room.