WTF is a 'desync'?
Clone it. Open the Unity hub and 'add' the project as normal. Once its open, go to the asset store, find PUN2 Free, (should be the first one that comes up if you type PUN) Download and import it, let it add all the shit it wants to add. You'll be asked for an app-id. HMU (Dave - up613235@myport.ac.uk) for this, as idfk what would happen if some random got hold of it. Probably be able to steal my identity. You got someone's photon app id and their github user name you basically have their bank account details.
Safe.