How to create a save and load game proccess like SCP: Containment Breach?

Ok. I have learned a bit about player prefs, but I have no clue on how one would go about creating a save game for it. I want it to be like SCP: CB where you can press a button in the game then exit then reload the save and be in the same xyz and have the same items (even though the extent of the items in my game is maybe 1 or 2 keys). Anyways, I was hoping if someone could point me in the direction of a good tutorial on how one would use them, or if not, then I have to dig deeper on how to do things like this cause I can't find jack. I know how I how I would use PlayerPrefs to define items in an inventory and that is about it. I am not asking someone to write a script, but I want to be taught how to do this. This ain't on Learn yet. :P