I followed all the steps, uploaded my game to itch, etc, but when I push the green button It says I don't have a game I can upload...
I'm shooting in the dark here, but have you switched your game from "private" to "public" on your game page ?
Yes. Indeed. Yup. Tried that. Does this add up to 20 characters yet?
Setting it to public worked. Had to wait a bit and refresh the site.
Great ! Just saw your game pop up on the jam page. All the best !