How to create a new random number when a button is pressed

I'm trying to create a program that creates a random number, and the user enters a guess and clicks the guess button. The program then tells the user if it is too high or low, or if it is correct. When the number is correct, I want to be able to click the Play Again button, which would reset all text in the GUI, as well as generate a new random number. Currently, I am able to click Play Again and clear the data, but I can't figure out how to create a new random number if the guess was correct. Any suggestions are helpful!

[GUI for program][1]
[Part 1 of code][2]
[Part 2 of code][3]
[Part 3 of code][4]