Updated for 7.0
On the left-hand side of the screen in the navigation bar, select My Group. This will take you here:
Under the table titled Member, scroll to find the member you want to send a message to.
Click the button with an envelope icon to the far right of their name under the column titled Send Message.
This will bring you to a pop-up window titled Send Message that will look like this:
Type the subject of your message in the text box titled Subject.
Use the text box directly beneath the subject to enter the contents of your message.
When you have finished your message, click the Send Message button at the bottom of the pop-up window.
These are sample names.