When loading the project for the first time unity may show multiple error due to some files missing, don't worry it's totally fine, unity will automaticaly reimport them without any problem, this allow us to sync as little as possible on the github repo.
While loading the project for the first time make sure to :
- use unity version 2021.3.1f1
- click continue or ignore if error appears while importing
- install universal rp in the package manager
- drag and drop the URP Renderer from "shader thing", to the Scriptable Render Pipeline Settings box in project settings under Graphics
- switch to 2D mode in the scene view
- add all the Scenes in the build settings panel
Now all you have to do is load any scene you want and get to work :)