On just about any page you can go to the line near the top, right where it says "Welcome, cje", then the next header is "Notifications" and a down arrow, click the down arrow and click on "Inbox". This will bring you to your private messages in your inbox. Click on the message you want to read. At the bottom of the box with the message, is an area which says "reply to private message" or you can click in the box at the bottom that says "quick Reply" and type your reply and click "send".