information help: What is the layout of a brochure? - Help.com

Since English-speaking countries typically read left-to-right, the SOP for a brochures (for the so-called tri-fold or tri-panel style - 6 small pages) is to presume they’ll read -
a) the cover - 1
b) the inside left panel (left-to-right) 2-3-4
c) then, the “5th” page is brought back down (the one that was initially flipped out of the way to read the entire interior)
d) then, the brochure is turned over to read page “6″ if it’s a rack brochure that can capitalize on another block of white space (as opposed to that page being used as the mailing label/postage imprint page)

Google for terms such as - brochure layout standard

Missed your second question -
a) obviously, this is the page that draws attention… practice KISS (Keep it Simple and Sizzly)
b) 2 thru 4 - this is where the important detailed information goes for continuity and ease of reading
c) page 5 - there’s different schools of thought about this page. Some prioritize this page since people “see” it on opening, even though it’s technically out of order from a reader perspective. Depending on what the brochure, this could contain bold selling points or testimonials, and contact info on it.
d) even if poor page 6 isn’t a mailing label page, it’s of low priority as the last to be read, so only supplementary info belongs there.