Thanks, that’s genuinely helpful!
The downloads page on gog seems to include ALL the manuals for all the Zork games, and I have no idea which ones I need for Planetfall, so having just the Planetfall stuff in one place is a real time saver.
The one you linked is labelled Apple II, but I suspect it doesn’t matter – I doubt the versions are significantly different, and it was pretty common at the time to print one manual that covers all systems anyway.
This game seems to have an intimidating amount of material to go through… Manual, letter, postcards, some kind of ID card… Do I need all this stuff? Do they have secret information I’ll need during the game?