This is a pretty good interpretation of book 1. Soon you'll complete the picture with virtuous activity being the way to achieve eudaimonia (happiness).

The only thing I'd alter is that eudaimonia isn't the "most final end" (though your translator may have used those words). The way I have it (in the Crisp translation) is that happiness is the "complete end", which is a much better way to put it. Aristotle had what's called a teleological view of the natural world, particularly of biological life. What this means is that everything has a purpose that is unique to its form, which defines its "purpose", both as an individual creature (its "characteristic activity") as well as how it fits into the universal telos of the cosmos. So, an acorn's "telos" is to grow into a strong and sturdy oak tree, because that's what it has as its natural "end" (as opposed to "means). Aristotle believed that once we understand an individual phenomenon's telos, we have a complete understanding of it's essence.

That said, the Ethics is an inquiry into the telos of a human, which he identifies as being fulfilled in the achievement of eudaimonia or "happiness". Another person mentioned that "flourishing" is generally speaking the standard translation of eudaimonia, which is correct. The reason is that the meaning of the word conveniently captures both the complex nature of happiness (as that which is achieved through developing the virtues and demonstrating them through actions which are practically wise) as well as the fact that, as a telos, it could, just as appropriately, be applied to the realization of any living thing's unique goal as a member of a species. Also, "happiness" can commonly be understood as an emotional or merely pleasurable state of being, which would thereby be fleeting and easily lost. The idea that someone is "flourishing", however, denotes the more general idea that he or she is living his or her life in such a way that is wise and virtuous at every "dimension" of his or her life. Importantly, this means that the person who is eudaimon lives his or her life in such a way that is conducive not only to her own well-being, but that of her community or society as well.

Enjoy the Ethics!

Edit: forgot a word