https://www.youtube.com/watch?v=Ekfio0gfn-Y
Add coin & collect it - Just type in component name to get its property, like “transform.position.y” - set isTrigger checkbox to true under Collider component so that coin won't block player's movement - Remember to make coin as prefab 
Add UI to display coin count - Canvas Scaler - Connect text to script
Add sound&music - assetstore.unity.com - Import from Package Manager - put audio file to audio source, put audio source to a variable (SerializeField) in playerMover script, play that variable in the script
Add another level - SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex + 1);
Add start screen - Canvas: Canvas Scaler: Scale with Screen Size - Match with height - Shift + Space to expand runtime window to fullscreen