Follow the above advice carefully. I like to arrange my results by size. So the junk usually falls down near the bottom, and if it isn't already marked as junk, I can easily see it is junk via either its size or title.

Keep in mind the LW Junk filter is not perfect & is a learning tool. So you need to train it. Some good items may show as junk so don't let those stay as junk if they are obviously good files. To unmark good files as junk, do the opposite to how to mark items as junk.