Everything that Uncle Joe says above, plus be sure to check out at least a few tutorials to understand what is involved. This is very well-understood technology so be sure you don’t waste time with dead ends. I have scribbled about the basics before as well:
Load/Save steps:
Don’t use the binary formatter/serializer: it is insecure, it cannot be made secure, and it makes debugging very difficult, plus it actually will NOT prevent people from modifying your save data on their computers.