In this documentation we cover only the parts that we have added in Xenon thus Bootstrap and other plugins information is not contained here, but you can find their documentation on their respective website or Github.
Buttons, panels, and other elements are not documented how they can be styled, instead they are all presented and included in the demonstration, you just have top copy them and use for your own purpose. If you want to learn more about these buttons, just refer to Bootstrap documentation.
Additionally, code commenting is present everywhere where you have choices to make changes, here is one example for Sidebar menu:
So you will find help comments while you are coding the template.