How do you refactor entrypoint classes in an Application?

I have this existing class setup. This is my entrypoint class.

public class AppManager {

    public AppManager() {

    }

    public void startApp(){
        doInit();
        if(doTask1())
            doTask2();
        else
            doTask3();
        createUI()
    }

    public void doInit() {
        InitClass initClass = new InitClass();
        initClass.init();
    }

    public boolean doTask1() {
        Task1 task1 = new Task1();
        return task1.doTask();
    }

    public boolean doTask2() {
        Task2 task2 = new Task2();
        return task2.doTask();
    }

    public boolean doTask3() {
        Task3 task3 = new Task3();
        return task3.doTask();
    }

    public void createUI() {
        UIManager uiManager = new UIManager();
        uiManager.createUI();
    }
    
    public static void main(String[] args) {
        AppManager appManager = new AppManager();
        appManager.startApp();
    }

}

I wanted to do some refactoring of it. I think it is doing a bit of things but I don't know how? I tried to create the task Specific class so that I can delegate the work to them.

But I think my entrypoint class is still doing a lot of things. According to good design "a class should only be doing one thing".

There are other tasks that I have ommitted intentionally for brevity.

Not sure if my question is clear but I just wanted to improve my code.

I have used java code in this case but I think this is still applicable to other languages.

How to refactor?