Buttons to initiate random draw + make result visible (with dry runs)

Hello,
I am using random draws in my survey. I would like participants to be able to do a couple of "dry runs", that is, I'd like them to have two additional buttons on a page. The first button should initiate a new draw, the second button should show the result of the draw.
After participants have understood how this works, they can initiate a draw which is final: for this one, they have to click "Submit" after initiating the draw (without getting to see the result in the same question). At a later stage, they will be told what the result of this final draw was.
I'm not sure how to do this--including in which part of JavaScript to place the code. The changes should be triggered by clicking custom buttons, and it's not clear to me if this should be done in "On Ready".
Thanks in advance!