importing media to iMovie from Photos

I’m struggling to import media to a new project in iMovie.  In iMovie I have selected the Photos Library and chosen Places from the pop up menu. I’ve navigated on the map to the place where all relevant videos and photos were taken on my iPhone. The map showing this place is in the iMovie window at top left, and alongside it at top right  a still from a video clip is displayed. The panel above the still tells me that there are 5 photos and 40 video clips available.

My questions:

• How can I best bring all of these media into iMovie?

 The help pages tell me to drag into timeline or library, but how? The displayed still image blacks out if I try to drag and drop it in the bottom section of the iMovie window and nothing else appears to change.

• Does  iMovie use a physical copy of the original media?  (I don’t want to waste space duplicating a probably  unwanted original clip but would be lazily happy to have iMovie simply reference it.)