Answer

As I recall, he writes this several times. Off the top of my head, at the beginning of chapter 1 there is:
“And the answer is that the Account of Creation is a deep secret, not understood from the verses, nor can it be fully known except through the received tradition, from Moses our teacher, from the mouth of the Almighty; and those who know it are obligated to conceal it. Therefore Rabbi Isaac said that the Torah did not need to begin with ‘In the beginning God created,’ and the narrative of what was created on the first day, and what was done on the second day and the other days, and the elaboration about the formation of Adam and Eve, their sin and their punishment, and the story of the Garden of Eden and Adam’s expulsion from it—for all this cannot be fully understood from the written verses. All the more so the story of the generation of the Flood and the Dispersion, whose necessity is not so great; those devoted to the Torah could manage without these verses and would believe in general what is mentioned to them in the Ten Commandments: ‘For in six days the Lord made heaven and earth, the sea, and all that is in them, and rested on the seventh day’; and the knowledge would remain with the select few among them as a law given to Moses at Sinai together with the Oral Torah.”
And on verse 6:
“And this too is part of the Account of Creation, and do not hope that I will write anything about it, for the matter is among the secrets of the Torah, and the verses do not require this explanation, since Scripture does not elaborate on it, and its interpretation is forbidden to those who know it—and all the more so to us.”
And there is more.