Saving and loading destructible terrain

I am new in unity and I am using the Saving and loading system from this video:

I have a destructible terrain like in mobile game sand balls. I don’t know how to save the progress that player made in game.
Can someone help me with it?

I haven’t found solution for this. My terrain is made from destructible blocks and every block have script attached and I don’t know what to save or how to save it. Can someone help me with it?