@OP; you have to understand that we wade through crap every single day where people are asking for information and never bother actually learning. Eventually, it becomes such a pain in the ass to deal with such people that many don't even want to bother trying to talk to them. So, with the hope that you'll learn something...
There's a lot involved. If you are currently connected to a LAN wirelessly, then you first want to see if you can see any other traffic. Certain configurations will put each person on their own little subnet or even simply deny traffic to locally-routed clients. This means that, in such circumstances, you won't be able to easily identify targets let alone get any good traffic from them. In other cases, encryption may be in use which would render packet capture all but entirely useless.
You'll need to learn A LOT of information to get good at any of this. You'll want to learn about TCP/IP, basic networking concepts like routing, firewalls, server-client connections, ARP, etc. You'll also need to be able to determine how to identify targets on the given network, which may require a variety of tools & methods. Furthermore, you'll need to learn how to locate targets, vulnerabilities and eventually exploit those vulnerabilities. You may need to learn a bit about numerous tools & toolkits, how to use them and why they're useful. You'll probably want to pick up a programming language or 3. Essentially..you just need to learn everything there is to know about anything.
You see, your current position is as the absolute beginner. There is a great deal of useful information on this website for getting started, including how to get started. Since you're asking the most basic questions, you're being treated as if you walked up to a group of bomb disposal experts and asked them something that they couldn't possibly explain in the 5 minutes that you're willing to spend paying attention. In the unlikely event that you ARE willing to spend more than 5 minutes listening, there's so much information that you'd need to learn that they would literally have to spoon-feed it to you as though you were a child. So, the response that you got was pretty much on-target.
If you'd like to prove that you're capable & willing to learn, you're welcome to do so. Until then, I'm going to consider this Board-of-Shame material just waiting to be moved.
