How am I going to use Crypto++ if I don't have a clue about cryptography?
The answer is: with difficulty.
There is nothing the more experienced people that use this library like more than a challenging security question to mull over. However, you may find you don't get much help if you ask a basic question with an answer that is well-documented elsewhere.
The library assumes you know in cryptographic terms what you want to achieve. Until you reach that point, perhaps you should do some background research? You should also know that building secure systems is difficult at the best of times. If you can afford it, you can get some professional help: Is there anyone I could pay to help me with this?
The good news is that there is a decent body of literature to help you. A list of recommended cryptography books is available at Recommended Books. A lot of good crypto information is also available on the web. See Related Links for a list of recommended sites.
(An excellent on-line glossary of cryptographic concepts and terms is at RSA Labs, which you can reach by going through the above link.)