@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_activity_layout);
    
    String[] mySteps = {"Name", "Email", "Phone Number"};
    int colorPrimary = ContextCompat.getColor(getApplicationContext(), R.color.colorPrimary);
    int colorPrimaryDark = ContextCompat.getColor(getApplicationContext(), R.color.colorPrimaryDark);
    
    VerticalStepperFormLayout verticalStepperForm = 
        (VerticalStepperFormLayout) findViewById(R.id.vertical_stepper_form);
    verticalStepperForm.initialiseVerticalStepperForm(mySteps, colorPrimary, colorPrimaryDark, this, this);
    
    ...
    
}

@Override
public View createStepContentView(int stepNumber) {
	View view = null;
	switch (stepNumber) {
		case 0:
			view = createNameStep();
			break;
		case 1:
			view = createEmailStep();
			break;
		case 2:
			view = createPhoneNumberStep();
			break;
	}
	return view;
}

private View createNameStep() {
	// Here we generate programmatically the view that will be added by the system to the step content layout
	EditText name = new EditText(this);
	name.setSingleLine(true);
	name.setHint("Your name");
	name.setOnEditorActionListener(new TextView.OnEditorActionListener() {
		@Override
		public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
			...
			return false;
		}
	});
	return name;
}

private View createEmailStep() {
	// In this case we generate the view by inflating a XML file
	LayoutInflater inflater = LayoutInflater.from(getBaseContext());
	LinearLayout emailLayoutContent = (LinearLayout) inflater.inflate(R.layout.email_step_layout, null, false);
	EditText email = (EditText) emailLayoutContent.findViewById(R.id.email);
	...
	return emailLayoutContent;
}

private View createPhoneNumberStep() {
	LayoutInflater inflater = LayoutInflater.from(getBaseContext());
	LinearLayout phoneLayoutContent = (LinearLayout) inflater.inflate(R.layout.phone_step_layout, null, false);
	...
	return phoneLayoutContent;
}

@Override
public void onStepOpening(int stepNumber) {
	switch (stepNumber) {
		case 0: 
			checkName();
			break;
		case 1:
			checkEmail();
			break;
		case 2: 
			// As soon as the phone number step is open, we mark it as completed in order to show the "Continue"
			// button (We do it because this field is optional, so the user can skip it without giving any info)
			verticalStepperForm.setStepAsCompleted(2);
			// In this case, the instruction above is equivalent to: 
			// verticalStepperForm.setActiveStepAsCompleted();
			break;
	}
}

private void checkName() {
	if(name.length() >= MIN_CHARACTERS_NAME && name.length() <= MAX_CHARACTERS_NAME) {
		verticalStepperForm.setActiveStepAsCompleted();
	} else {
		verticalStepperForm.setActiveStepAsUncompleted();
	}
}

private void checkEmail() {
	...
}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
	...
	super.onSaveInstanceState(savedInstanceState);
}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
	...
	super.onRestoreInstanceState(savedInstanceState);
}