How can I change 'Order in Layer'

Hello, I’m a beginner at unity.
I downloaded ‘Monster Prefab’ from Asset Store and use it.
However, the value of ‘Order in Layer’ in ‘Sorting Group’ is 200 and changes to -2 when playing.
It works well, but I can’t see it because of background.
I gave the background as -3 to make it work, but I want to know how to fix it.
what should I do?

That means there’s some piece of code changing the sorting group. In Visual Studio while your project is open, press Ctrl + Shift + S and search for sortingOrder = and sortingLayerName =. This should show you the way. Remove or fix them.