As per Alex's request, from now on, any time you can't find something in the rulebook, post about it here and I'll update this post. I'd start with an example but I can't recall just now.
ACKS core:
ENCOUNTER FREQUENCY: How often do I roll?
RULE: Check for a random encounter every hex and night when travelling through wilderness, every week in borderlands terrain, and every month in civilized domains.
SOURCE: In the Campaign section, under mage dungeons.
This post in particular about wandering monster frequency in various kinds of land (settled, borderlands, wilderness) is one that I did not figure out from the rulebook, and didn’t know until seeing it on the forum.
Filling out a character sheet to "get the feel of the game" ...made a Dwarven Craftpriest. On the character sheet for this stuff below..I couldn't find it right away. I posted a Proficiency question here on the forum and they pointed out this stuff is buried on page 92/93 under Dungeon Adventures:
Open Door
Detect Secret Door
Hear Noise
Find Traps
Circling back around to ACKS again...and found this "living document" hasn't been touched since I was in it 6 months ago- guess this thing needs some life support. :)