This hint must be for people who don't like using their mouse. Otherwise clicking the download button on the far right of the tool bar does the same thing.

Nope, not that.

it's for people like me who want to download Youtube and Vimeo videos, because the best the world can offer us for internet connections are pokey DSL. So instead of waiting for your video to buffer, you can download what you want and watch it later. The way to do that is to find the download link in your activity window, copy it, and paste it into your downloads window. Having that window gone has made it a pain to do so. Option-double click is a workaround, but why take a step backwards?

I do not see any download button in my tool bar and see no option to place one there. Please tell me more.. Thank you

yes... I avoid the mouse whenever I can.