There are probably two mistakes that beginners make related to your question. The first is that many of Elements' features must be used in the Expert tab rather than the Quick editing mode. The second is that, even in the Expert Mode, a photo has to be open in the editor before the menu commands come to life.
Phinny's response has covered both of these issues, and also a third, which I suspect does not apply here, namely, the Haze Removal tool does not work on Black and White (greyscale) images. So, I think Phinny has covered all of the bases.