I've realized over the years that it takes many conversations to fully explain the advanced theory. I've tried to re-create for you the process that my friends who understand the theory went through. People new to the theory usually ask if something is advanced, I tell them that is or it isn't and why, then that person goes away to think about it. This is repeated over and over until finally they get it. Since we can't really go through this process together, I'll attempt to anticipate your questions and answer them. I'll also give you examples that have nothing to do with music, but everything to do with the theory. For instance:
If you have a spotted dog and you name him Spot, this could be advanced or overt. It would be overt if you did it to be ironic or funny. If you did it because you like the name Spot or had a dog named Spot when you were a child, that would be advanced. Even though people might think that you are being funny or that you aren't creative, you named your dog Spot to please yourself. If you have a dog with no spots and you name him Spot, that is overt, no matter what.