There's good stuff, and it explains things well. And then it gets to this:
It probably used to be the case, many centuries ago, that any given person lived within one large, overarching culture. Such a culture may have been complex, but it was not multiple. If you had lived in Britain during the Dark Ages, for instance (say, around 900 C.E.), everything around you, everything you encountered during the day, probably everything you knew about, was part of the same system, the same group identification, and thus the same culture. You saw and spoke only to others of your own group. Different aspects of life, such as work, religion, or government, were all closely interrelated; they all manifested the same overarching culture to you. The same situation may still be found in some tribal cultures around the world, where people are primarily enveloped in a small, single group of people and surrounded by the artifacts that represent that single group. (24)
So, where to begin?
I'll let you at it.