按下按钮后切换屏幕？使用LibGDX

Currently working on a game for school and I ran into a problem. I created a Main Menu for my game with the buttons (Play, Level Picker, and Settings). What I'm trying to do is when the "Play" is pressed it will switch to a different screen where the user will play. The menu is under the name of MainMenu and the screen I want it to switch to is called StartGameScreen. I've tried looking online for my answer but can't seem to find something that will work. If it helps here's my code for the play button. Any help would be fantastic!Currently working on a game for school and I ra