You've jumped into the deep end of the pool with weights strapped to your ankles here. Your lack of understanding of even the basics has resulted in you using phrases that are meaningless and don't apply to Bitcoin at all, such as "private address".

What are you trying to accomplish here?  Are you just wanting to learn more about the technical details of the bitcoin protocol because you find it interesting? Are you trying to create software that interacts with the Bitcoin network in some way? Are you just trying to receive some bitcoins from someone that wants to pay you with bitcoin? Do you already have some bitcoin, and you're just trying to send it somewhere?

User ABCbits, earlier in this thread, has linked to some good resources for learning a bit more about some of the technical details of keys and addresses. Hopefully that will help, but I'm not certain yet that it gets you any closer to what you're actually trying to accomplish.