Then you need to learn how networks, client/server applications and all that work. Then you need to determine what exactly it is you want to test for security. Once you know that you need to read up on how exactly they work. After you've done all this correctly, you should be in a position to answer your own question.
>>4
Imagine I'm travelling from A to B, and I'd like to log a list of all wifi networks, and some details of those networks. (encrypted? type of encryption?)
The bad question is: "How do I do that"
A better question is: "How do I find out how to do that using backtrack, since asking here probably isn't going to help"