I work a lot with virtual copies (the before-after function is a bit clumsy, and not so good for exploring different interpretations of an image).
There are keyboard shortcuts for so many things, but not for "create a virtual copy".
Or is there, and it just wasn't in the book?
If there isn't, is there a function, where you can create your own shortcuts?
The shortcut is Ctrl-' (Windows) or Cmd-' (Mac)
You can't currently create your own shortcuts - hopefully a future version.