itch.io

It looks like you uploaded the entire Unity project folder, but I don't see a Build folder in there. You need to build the game in the Unity Editor. It will prompt you to either select a folder or create a new one. You need to upload all of the files it creates in that folder, and only those files. Here's the page about creating builds from the official documentation: https://docs.unity3d.com/Manual/PublishingBuilds.html

There are also lots of tutorials out there if you search around. Best of luck!