First click on the P.M. button in the menu, another window will pop-up, from there you can access the "Send a U2U" screen, by clicking on it at the top. Place the users name in the "To" field, and then insert a subject and a message and click "Send". 。
You can view all the members by clicking on the Members List button in the menu.
By clicking on the "Search" button in the menu. Then inputting what you wish to search for, you can restrict where you search with the drop down lists.