Are you using the mac version or the windows version? It's very different between the two. On a mac you must be in the editor in expert mode to create a contact sheet, which you do by going to File>Contact Sheet II. If it's grayed out, you probably need to click the word Expert at the top of the editor window.
99jon has been giving you the windows directions. The red and green buttons you mention usually only appear in the editor and you need to be in the organizer in windows.