Asking a question is a skill: dumping a lump of code and adding the text "Cookie container means?" doesn't represent a good example of it's use.
Remember that we can't see your screen, access your HDD, or read your mind - we only get exactly what you type to work with. So if your code doesn't do that you expect, or does do something you didn't, you need to explain that to us with sufficient context that we understand exactly what you are trying to do, what happened when you did it, what you expected to happen, and what you have tried to either find out why, or fix it.
Without that, all we can do is refer you to the standard documentation:
CookieContainer Class (System.Net) | Microsoft Docs[
^] which you could have found with a trivial Google.