To empty your folders you first go to private messaging. You will see a green and red bar at the top. You will also see a Empty Folder option which you click on. Then you go to the pull down window to get to the second folder and do the same thing.
For messaging you go to the forum page and click on the forum you wish to use for you message. You then look on the right side of the screen for forum tools. Click on forum tools and you will find an option to leave new message.