“And nobody for miles.”
For miles describes a distance of many miles. Nobody for miles conveys that no one is anywhere nearby. A mile is about 1.6 kilometers; the phrase shows how remote Frank's village was.
A2-06 / CEFR A2 / EPISODE 06
Comparing your hometown with your current city
SceneLooking at the night sky and discussing home.

WORDS & CONTEXT
For miles describes a distance of many miles. Nobody for miles conveys that no one is anywhere nearby. A mile is about 1.6 kilometers; the phrase shows how remote Frank's village was.
Putting how after an adjective makes a short follow-up question: "In what way ...?" The full sentence would be How were they brighter? They refers to the stars of Tina's home. Tina has said they were much brighter than the stars here, so Frank asks her to describe them.
Look like ... means to seem similar to something, and just above ... means right over something. Tina compares the brightness and closeness of her home's stars to lanterns hanging overhead. She is not claiming the stars were really just above her head.
This means "If I visit, I'll bring a helmet." Here I'm bringing ... is not about carrying something now; it states what he plans to bring at that time. Frank takes Tina's image of stars just above her head and jokes about protecting his head. No visit has actually been planned.