I need help

Well, I could tell you how to trade, but it depends on what you are trading with. Is it a person in the game, or one of your friends. Because, actually, trading became a whole lot easier on the Nintendo DS. The whole process is simple, you get your Pokemon that you want to trade, and go to the second floor of the Pokemon Center, then you talk to the third woman who will ask if you want to trade or battle with a friend. You will enter a big room, and in that room, you should see your friend. You need to have your Nintendo DS's connected so you both need to play the game facing each other, and there should be a green bar like figure at the top right of your screen. That signifies that your connection good. Then you just trade Pokemon, that is pretty much it. When you are in the room, talk to your friend to begin trading. Hope this helps.

To trade without other friends codes. Goto the GTS, it's a town, if I remember in the bottom left. Have the internet for the DS. Go there. You talk to the lady at the desk. Then you will be online, and can look at many Pokemon, but you should have atleast seen the Pokemon first. Before you can trade for them. If it's a Pokemon like a charizard you will need to have seen it, before you can trade for it on GTS. GTS is Global Trading Center. Its a large building.