When you call someone there's a button with a camera icon on it. You push it and so does the other person and you hold your phone as you would with it on speaker phone. They can either see you or see what your phone is aiming at depending on which view you choose.
Call someone who can do FaceTime and call there number. It will call the person for FaceTime and they will ether respond or not respond. But if you still don't understand ether go to YouTube and look it up or go to the apple store and ask them.
You are able to chat with another person who has an iPhone 4 or iPod touch only using wifi connection. You can connect with someone who has an iPhone by choosing FaceTime with their phone number. If you want to connect with someone who has an iPod touch, then you will need to enter their email address they linked their FaceTime account with. Remember you can only use on wifi.