This doesn't make sense. If you've written all the above code then determining where to put a ShowBoard call should be trivial. Have you written it or have you got it all from other people suggesting you some solutions?
But I can't suggest where to put the call to ShowBoard simply because I do not know where you want to put that call. Only you know where you want the board to be shown.
Also I'm not sure what you expect would be shown, because after ArrangeQueen has returned, it looks like the board will be full of asterisks (*). Do you want to see 64 asterisks or something else?