You find that in the same place where Congress is given the power to criminalize the possession of rocks, in the same place where Congress is given the power to define who shall or shall not be a natural citizen (as opposed to a naturalized one,) in the same place where those in the US when the US came into existence were made US citizens by statute or other man-made law—such as a Constitutional provision.
In other words, you don't.
Congress has no power to criminalize the possession of rocks. Because no such power is granted to them in the Constitution.
Congress has no power to define who are citizens naturally, without any need of a naturalization statute, because no such power was granted to Congress in the Constitution. Congress was granted the power to make naturalization rules, but the power to define who are natural citizens was very pointedly not granted.
In fact, that's how the Supreme Court in Minor vs. Happersett was able to rule that Mrs.Minor was citizen without considering any statute, and without considering the 14th Amendment. The fact they could do that that way, by natural law alone, was a key point in the chain of reasoning that justified their principal holding that Mrs. Minor had no right to vote, because women had always been citizens, proving that the privilege of voting was separate and distinct from being a citizen.
Nor will you find anywhere in the Constitution, nor anywhere in any Congressional statute ever passed, that makes or made anyone a US citizen who was here when the United States came into existence. But the country nevertheless had millions of citizens at the instant it came into existence, in spite of there being no man-made law that made them so.
And except for those who became citizens by naturalization, there was no law that made most people born in the US citizens until the 14th Amendment was passed. But they were citizens nonetheless—as the Supreme Court ruled in Minor vs. Happersett.
Thank you. Very powerful idea here.
The "bootstrap" does not exist.