Conversation so far:
What was the break?
Herc used the record to focus on a short, heavily percussive part in it: the "break".
What did the break consist of?
Specifically, DJ Kool Herc: extended an instrumental beat (breaking or scratching) to let people dance longer.
Did people like it?
...
[This] helped lay the foundation for a cultural revolution.

Question: How did it lead to a cultural evolution?
Self-contained rewrite: How did the break lead to a cultural evolution?