As soon as you have a NODE Ambient in your system, you have access to all the widgets available for the NODE. This means that the colour wheel is also available. If you don't want it on the app screen, you can simply delete it. To do this, press and hold the widget and then drag it down to the centre into the red trash can.
Now you can add another widget for lights via the side menu -> Add widget -> Lights. All you have to do now is select the widget you want.