The instructions are simply this:
The No-aids post is your promise not to use external aids during the competition, and you'll get listed in the separate section.
The Open is to effectively cancel the Signup, should one for some strange reason decide to start using external aids. You'll only be listed in the Open section.
The Exclude-me is if you really want to be explicitly left out of the lists entirely. You won't be listed in either section.
The effect of never posting to this thread (or posting other than as instructed here) is exactly the same as posting Open to it.
Please note: "Dumb" computer software scans the signup thread for one of the three options, and ignores everything else. Specifically, it only pays attention to the very first line of each post. So posts which don't follow the directions are gonna be what we old-school assembly language programmers called "no-ops".
Please note: The automatic signup scan takes place just at the start of Freecell Saturday. So someone’s signup halfway through Saturday is not (automatically) going to be valid for that day’s competition. It is possible that if I‘m around, and I notice a signup during the day, I might run it manually. No promises, though.
Technical note: This mechanism manages the three 'logical lists' of open, signup, excluded. I don't maintain (how could I, really) an open list, though. You request Open to retract any previous request to be on one of the other two lists.