Find a Post with the Person's name and Click on the name, a window will open with Options in it, one of which is "Private Message", Click it...! Also on the Top of what-ever page One is on is the word "Notifications" next to Your Name...! If You have a PM from Someone it will bee in there, just Click it...! You should bee able to Reply after that...!
One can also look near the bottom of the Home Page and see Who is Online, Click the Name of the Person One wants to PM and Click... Send Private Message...!
