Setup keyboard / gamepad navigation on more than one panel menu

Hi all,
Here is the setup
One canvas containing two panels.
Panel 1 contains a game object with buttons for the Main Menu and Panel 2 is for the Options Menu.
If you click on the options button of the Main Menu it opens up the Options Menu.
Currently I have the buttons of the Main Menu setup for automatic navigation. I can then browse through the buttons of the Main Menu, I have the buttons of the Options Menu setup with no navigation.
I want to know and understand how I can change the navigation (dynamically through script??) to the buttons of the Options Menu and then disable navigation of the Main Menu and go back and forth.
In general an easy way to go back and forth between different panel navigation in the same Canvas.
I have looked into Selectable and see that this could be useful but unsure on how to implement this
Thanks in advance for any feedback.

 

Didn't realize that you can just change navigation to explicit and select the previous and next selectables right from the component editor. duh, This script https://github.com/AyARL/UnityGUIExamples/blob/master/FlowControl/Assets/MenuController.cs
is still a big assist for controlling with script.