Browse to the member’s profile that you want to send a message to, and click the Send Message button located to the right of their profile image.
A pop-up window will display giving you a text field to type a message to that member. There is also a window to enter a subject line.
Click the blue Send Message button under the window and the message will be sent to that user.
Note: If you are not friends with a member, you will not able to send them a message.