Apple provides the answer for you right here.
When you call this method in your shipping app and a rating/review request view is displayed, the system handles the entire process for you.
To help clarify this some:
Apple spells out point 3 here on the provided link:
When you call this method while your app is still in development mode, a rating/review request view is always displayed so that you can test the user interface and experience. However, this method has no effect when you call it in an app that you distribute using TestFlight.
And for point 5, here is what Apple has to say on it at the provided link:
However, customers aren’t able to rate or review an app that was downloaded using an iTunes Connect promo code.
So sorry, you can't pad reviews via promo codes ;)
Submit button is disabled in development version and the View doesn't even show up in Test Flight versions.