Why can't Finder open two drives at once?

I am a photographer, & frequently need to move files around between folders on 3-4 different drives (internal/external/memory stick, etc). This is my first Mac, & I'm astonished to find that the 'Finder' window will only show one drive at a time! I cannot open a new window for each drive & simply drag the files to the correct folder, as I can in Windows, so I end up having to drop the files somewhere on the top level of the target drive (as this is all I can access of the other drives, on the left side of the Finder window). Then I have to go into that drive & move the files to where they're supposed to be. Or create a pointless folder on the desktop & then move the files from there. Then delete the folder. This is a terrible waste of time! This is like technology from the 1990’s – is this really how it is supposed to work? It’s so bad I thought maybe there was a fault with the computer; or have I missed something basic? In Windows you simply open a new window for each drive - & drag & drop the files around. Simple & quick. Any help would be appreciated.