What is the limit of x^(1/x) as x approaches infinity?

There is an explanation in the last box at the very end of this page: Pauls Online Notes : Calculus I - L'Hospital's Rule and Indeterminate Forms

But I don't understand why he set y=x^(1/x). Where did the y come from? And how did he arrive at ln x / x ?

This is the only step I'm having trouble with but it appears to be pretty basic. I'm either having a huge mind fart or I'm overlooking something.

Explain please. Thanks in advance!