Here is the code you must write to add the button ''_buttonGoBack'' to the second screen
<source lang="java">
ButtonField _buttonGoBack = new ButtonField("Go Back", ButtonField.FIELD_HCENTER | ButtonField.CONSUME_CLICK);
_buttonGoBack.setChangeListener(new FieldChangeListener() { public void fieldChanged(Field field, int context) { UiApplication.getUiApplication().popScreen(); } });
add(_buttonGoBack);
</source>
