As Lexsonn pointed out the project files were shipped instead of a build. You said you are new to development and weren't sure of the difference, that is totally fair. While I wait for Unreal to boot up maybe I can help a bit?
What you've shared is similar to what is given out when a developer says "hey guys, my game is open source, here you go!". And a "build" or export of the game would typically result in an .exe file that can be double clicked to play it (at least for windows).
I haven't use Unreal in a few years but if you search for "Unreal Project export" and look for links from Epic Games it looks like they have a tutorial called "How to Build Your Game in Unreal Engine 5 - Super Easy". Not sure if I can do external links here, but here's a direct link:
https://dev.epicgames.com/community/learning/tutorials/oPna/how-to-build-your-ga...
Once you export/package it to a new folder, you can zip whatever is in that folder and re-upload your game! There's still a bit of time to do this. If you can do so it will help others be able to play your game. Currently, I believe they would need to have unreal engine installed to try what you have here (and then wait for shaders to compile). Oh, also I highly recommend trying the exported EXE file before uploading to ensure it works as intended (sometimes things like accessing files can get weird between development and exporting).
Sorry for the long comment, hopefully it is helpful & welcome to game development! 😁