Beginner Question: long-tail cast-on questions

I am brand new to knitting and am trying to cast-on with the long-tail method. I have a couple of questions: 1) as I add stitches on the cast-on row, does the tail remain hanging in its initial position at the slip knot, or should it advance with each stitch and remain right next to the thread from the ball of yarn? 2) If the tail does advance with each stitch, what do you do with any that is left-over at the end of the first row (do you knot it and cut off the excess)?
I will sure appreciate any help with these questions. Thanks!

Yes-yarn tail hangs of first stitch with slip knot. And you weave that end in later. Or use it as part of the seam.

The tail moves along the needle away from the slip knot as you cast on. When you [I]knit[/I] the first row, it stays put. If it’s too long when you have your stitches cast on, you can cut it to about 6" or so to weave in later, or wind it up a little to use for seaming.