How to make save levels and how many stars each level is passed, like in Angry Birds? And how to save the collected coins on a level so that when the level is restarted, those coins that were collected in previous attempts did not appear any more?
Try this: Persistence: Saving and Loading Data - Unity Learn
and/or this: Unity - Scripting API: JsonUtility
Keep track of what’s been collected, so you don’t spawn them when replaying the same scene?