What was the problem? Here are some general instructions for creating a Godot web export:
In Godot's Project->Export window, do "Export Project" (not "Export PCK/ZIP"). Make sure the main file is called "index.html", itch.io requires this. Then package all the files in a ZIP-file so that the files are in the root of that .zip and not in some subfolder. On itch.io's Edit Game page, change "Kind of Project" to HTML, upload the zip, and then tick the "This file will be played in the browser" check box. Remember to save the changes. The game should now at least load & run. You can tweak the other settings later, and don't forget to change Visibility to Public to make the game available for everyone else.
If the game runs, but doesn't play correctly, try checking the console for errors first (F12 key in browser usually). You can also add printing in the game + upload + check again.
If the game loads external data files dynamically during the game, like load("intro.txt"), you'll probably need to include these in the export folder before zipping it. The other option is to try to include these within the export settings on Resources tab.