Here above , you can access your Private Messages by clicking on    "Private Messages " beside your avatar at forum's main page.

Below , is the view of Private Messages' Page. You can send a                    PM ( Private Message) by clicking on COMPOSE MESSAGE .

Tip: You have a green meter which determine your space used take care if you used it up you will never receive any PMs , deleting un necessary PMs will reduce your space used

OR another way is to go to your Usercp and Click Compose

Here , when you click on Compose...this page will appear. You must enter a Recipient(s) name i.e. : a member name. Then you must enter the Message's subject like " Hi " or " Hello"....Finally type your message and click on "Send Message " button

Tip: You Can enter only the First 3 Letters of a member and automatically will be selected like the picture below

IF You got a PM you will be notified by a popup like this :