Need help adding feature into my program

I'm making this program that generates raffles and selects winner. The bit I'm stuck on is adding feature where a user clicks on a button called enter draw and is automatically given a random raffle.does anyone know to add feature where a user clicks enter draw and the random raffle is stored and used to select random raffle here's my code.

See More efficient algorithm to randomly select raffle winners in Python And scroll down to the end where you will see my code