Split/separate exported files/classes in Android Studio?

Hi All
Have just exported and imported to Android Studio … all works fine but the whole project is now contained in one java file … everything nested within

public class Sketch extends PApplet { }

The app in Processing uses multiple tabs for classes and functions etc so is there any way to separate these out as individual java files in Android Studio, or does everything have to go inside the PApplet {} braces?

Cheers
Mark