I think you’re imagining this harder than it is.
You can upload whenever you like, whatever you like, as long as the “whatever” is
a) something for which you are the copyright owner or you know to be public domain (if the maintainers have concerns, they may contact you, but there’s no problem here if it’s something you wrote);
b) related to IF: a game, an article or fanzine about IF, an IF development language (or libraries/extensions for IF development languages), cover art, feelies, etc.
c) (this probably goes without saying) not something inherently illegal to have, such as child pornography.
In general, this is considered a pretty normal thing to do when releasing a new IF game, but it’s not required if you’d prefer to host your game somewhere else. Authors submitting to competitions, such as the IF comp, are often required to agree that their games can be uploaded to the archive as well. One possible drawback: though the archive maintainers will, of legal necessity, agree if someone really demands to have a piece of IF taken down, they really, really, really don’t like to do that, and may try to talk you out of it. So the main reason not to send something to the archive is that you think you might want it to be a temporary publication. The archive tends to keep stuff around forever.
To do this, you click here:
ifarchive.org/cgi-bin/upload.py
…and follow the instructions. Choose your gamefile to upload, and fill in the form with whatever information you want people to have about your game.
There is a slot where you can type the directory you think your game should wind up in, but really, if you find that confusing, leave it blank. It’s there for the benefit of people who are quite familiar with the archive and may be submitting something unusual. If you’re not, the maintainers will file your game with other games produced for the same VM, so in your case the game would go in a directory reserved for games in TADS. Any description you give for your game will go into the index of the directory, to help people find your game, and will also be published to RAIF at some point; every few months or so the archive maintainers publish a huge list of recent updates to the archive. (I’m not sure how many people actually read it, but it is useful for those who maintain other IF sites and want to make sure they didn’t miss any game announcements.)
If you do make a mistake, or later want to replace a version of a game with a new, bug-fixed one, you can always do this by emailing the archive maintainers, who are very friendly people. Frankly, the IF archive just does not get so much traffic as to have become madly mechanized. So there’s a low risk of your doing anything “stupid”.
(And no, no dental plan, sorry.)