Tartan is correct. Go into your settings (click tab at top right of page), then scroll down about halfway and on the left side of the screen, click on "General Settings". Go all the way down to the bottom of the page under "Miscellaneous Options", at the "Message Editor Interface", make sure the option "Enhanced Interface" is selected. Then click "save changes" at the bottom of the page and you should be good to go.
I recommend opening this page in another tab so you can click back and forth between these instructions and your settings page without getting lost.
