Hello everyone, I’m wondering how to save all scene objects for example if I press the Save button, or load the when I press the Load button… seems hard.
Any help is appreciated 
On the basic level you need to serialise all gameObjects into a file. And vice versa load them back out.
You may also want to serialise AI data and various other information too.
See a similar question here: How to script a Save/Load game option - Unity Answers