For example, end turn with the big X icon has a 5 above it.  I assume these numbers are the hotkey I can press to execute this command.

But, pressing 5 does nothing.  In fact, pressing 1 - 5 does nothing.  Are these not working yet?

thanks for the question! We may change it to work that way at some point but for now, the numbers open the command menu and SPACE executes that command. It should be marked next to the button in the same font/color as the other tooltips.

Got it.  Thanks.  It's no big deal, but the space to execute should be mentioned in the tutorial.  That's fairly unintuitive.  Or, maybe I'm just dense.