I apologize first, because this has been asked, like in
But I don't get how to use them.
Some codes in these answers don't work when I just copy-paste blindly (because I really don't understand them.)
Are the above methods the standard way to "Treat variables as local by default (No need to specify them, like in Module)" in Mathematica? If so, please give me a working example, please.
I think there should be a standard way to do this, but I can't find it in the documentation.