If we want to submit do we build the game or zip the project files and submit basically how do we submit
Personally I provided two options: the full zipped project folder, that can be opened up in Unity Hub, as well as an exported .UnityPackage file, so someone can just import it into any existing project (albeit without layers set up).
I have no idea what others would prefer, but I figured that's flexible enough for anyone familiar with Unity to get into and start working on.