I would caution against putting an E-mail address in a post as it can be seen publicly without being logged in. The better thing to do would be to click on the person’s name or image. That will take you to their Profile page. Once there, you can post messages on their WALL or you can do a PUBLIC MESSAGE or a PRIVATE MESSAGE. A PRIVATE MESSAGE is only between you and the person that you are sending it to. The others can be seen by anyone who is logged in.
What are you having difficulty with? How can I help?