From the main screen 4 menu icons are displayed, clicking the corresponding navigation key will open the corresponding menu. Clicking the back key from the main screen will also show the label for each menu.
Inside the menu any sub-menus of that item are shown below, sub-menus and menu items can be accessed by clicking the corresponding navigation key.
If an error has occurred then the General Settings icon may display an exclamation mark, this will be cleared when opening the Error Log.