Click the "My Forums" cube.
Select a forum and click on the subjec you want to post a message to.
You can read all previous messages in the list below. The messages that you have not seen yet, are bold. The most recent message appears first.
Enter "My message". You can use the button "Attachment" to add one or more files (e.g. a picture or Word document). Finally, click the "Done" butto to add your message.