RANDOM
ACCESS.

This host did not expose a usable folder listing. Open metaindex.html in a text editor and add your HTML filenames to FILES near the top of its script:

const FILES = [
  "index.html",
  "another-game.html",
  "something-strange.html"
];

Names are relative to FOLDER. Use "./" for the same folder, or something like "./experiments/" for a subfolder. A manual list also works when opening this file offline.

For automatic discovery, put your pages in a folder with directory listing enabled. Many hosts show index.html instead of a listing; ask your host how to enable listing for that folder.