I appreciate the help - so no need to explain the questions:
1) Keyboard strokes - I held down the "control" button on my keyboard - last button, lower left hand side and clicked on my desktop with my mouse.
2) Keyboard - Mac "Magic Keyboard with Numeric Keypad" that I received/purchased when I purchased the Mac.
3) Mouse - "Magic Mouse" - similarly, received/purchased when I purchased my Mac - notethat this may be a replacement but if so, has been in use or a few years.
Interestingly, I just noticed that many selects are greyed out in the Finder Menu - see the attached image. I only mention this because there may be a connection between the two issues.