[Docs] Explain ways components can be nested / structured

[nikos]

It be great if for example the "Usage" page (or even an own introduction page) explains on what are typically ways to nest the Material UI components properly, probably in a way consistent with the Material Design structure documentation.

[mbrookes]

AppBar and LeftNav already are consistent with that. There is no bottom bar (use flexbox), and everything else is specific to an individual app.

What did you have in mind?

[nikos]

This issue is not about AppBar and LeftNav, it is about how you nest elements over all. Also mentioning AppCanvas might be an idea.

[mbrookes]

it is about how you nest elements over all.

Okay, thanks.

Dupe of: #3066