What advice does Thoreau offer to the younger generation of Americans about their choices in life?

From the text:

“How could youths better learn to live than by at once trying the experiment of living?”

“Which would have advanced the most at the end of a month—the boy who had made his own jackknife from the ore which he had dug and smelted, reading as much as would be necessary for this—or the boy who had attended the lectures on metallurgy at the Institute in the meanwhile, and had received a Rodgers’ penknife from his father?”