[Generate Press] Read more on a page

Hi,
I’m copying and pasting, and not succeeding.

I’d like one page, visitor arrives and can see 3 headings with an excerpt. Visitor can then read more of the relevant section.

I’ve added code from codex post that should enable <..more..> in text, but it seemed to crack my dashboard function (media upload) instead.

Posts (instead of page) would work only if info can unfold and visitor can still scroll down to see all 3 sections.