Help me analyze the sentence composition, be more detailed, thank you!

Every year, 3 million people migrate from poor countries to richer countries. People follow developing countries for the same reason that they emigrate to rich countries. In a word, it is the structure of the main family table. Note that the structure from ... to ... is translated from where to where followed by nouns, and the rest can be translated literally according to the meaning. In the second sentence, there is a noun as an adverbial after the within table. Note that as is a fixed collocation, and the cannot be omitted.