If you want to include more information about an object or to notify your colleagues, you can post a message. To do this, first select a specific object and click the Messages tab. You will see the screen below.
If you want to notify other users as well, click Mention user. By selecting the name from the dropdown box, the selected user will be able to see the message on their dashboard.
If you only want to place a comment, write the body of your message and click Post message.