Okies, if you want to send a private message (pm), you have multiple options. You can click on the 'pm' button, which is located under every post made be someone. Then you come to screen that looks a lot like a 'post-send' screen, the only difference being an extra field to fill in the username of the person you want to send the pm to! If you've clicked on the pm button under someone's post, his/her name will be filled in automatically!
An other thing you can do, is, if you wish to reply to an pm that has been sent to you, clicking on the 'post reply' button, located under the pm you're reading.
Also, if you go to your inbox, by clicking the pm-thingie in top right corner (between 'profile' and 'log out') you can make a 'new post'. Then all you have to do is fill in the username yourself and you're ready to go!
I hope that helped
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