To use the inbox function, simply click on the envelope icon at the top right of your Margo dashboard.
This will open up a new chat message pop-up, where you can start to draft your message. You'll be able to message anyone on your team, and if you are assigned to multiple teams, you'll be able to choose the recipients by company.
If you're looking to check your messages, X out of the window, and view your messages to the left. As you click them, you'll see the full message to the right just like an email inbox.
To compose a new message from this view, scroll down and click the + sign. To reply, while viewing a selected message type your reply in the box at the bottom.