Ctrl+F and try skipping to ";;;; The Basic Macros" section on that quick start page. Is that about the right level?
For many of the "popular" languages, a simple cheat sheet showing the equivalent control structures in a common language might be enough for a typical programmer to get a handle on it quickly. But Lisp is not an Algol-family language. It's different enough that such a document would fail to convey what makes it interesting. There's an inferential gap that must be bridged first, and it's difficult to do that quickly; a programmer mistakenly [expecting a short inferential distance][1] may not have the patience to "get it".
[1]: https://www.lesswrong.com/posts/HLqWn5LASfhhArZ7w/expecting-...