I’ll put your name on the list, and you can visit that page on the day for the video link to join via Zoom. No need to fuss with a “formal” RSVP unless you want to try it for fun. Incidentally your tweet which mentioned the event post has created an informal RSVP on the page already. 🙂
Most are logged into the system with their website which will give you a one-button RSVP link. However, most have actually RSVP’d on their websites and sent a webmention to that page for their avatars and details to show up on the page. (Here’s mine.) If you don’t have your webmention sender live yet, you can do it manually: https://telegraph.p3k.io/send-a-webmention.
If you want to go through the exercise and need some help, pop into the IndieWebCamp chat and we’ll help you get sorted.