First step is to register your Friends with the Center Admin on the right of the Pokémon Center's basement Wi-Fi Corner. Upon your first visit, she will give you the Pal Pad which contains all of your friend's details, records and your own personal friend code. This code is vital for your online Pokémon endeavours. Once you go into the Pal Pad, and register a friend, you can go to the desk and conenct, providing of course, you have a valid WiFi Access Point within your DS's sights (Wireless sights, not physical). Once there, you will be in a lobby of sorts which lists all of your friends that you have connected. From here you can select the choices; Battle or Trade

Trading is the main option you'll be looking for in order to complete your Pokédex. if you have Diamond and your friend has Pearl, this is an easy way to get the Pokémon that you want. The trade works like all trades have worked through Pokémon games in the past so the setup shouldn't be that hard. Just select the Pokemon you're going to trade, they'll select theirs and it's traded. Voice Chat is usually active through the entire trade so you can discuss with your friend what you want right there and then. Handy eh?

Battling, the way you test your skills with your friends. Battling can be done one of two ways; Single Battle or Double Battle. Unfortunately, you are only able to battle one friend at a time over WiFi. Battling works the same way as it does throughout the entire game so be sure to practice and EV train your Pokémon before you battles with your friend's on the 2D plain. Voice Chat is enabled as default during battle so that you can heckle your friends if you feel the need has arisen.

In the Battle Tower in the Battle Area, there is a facility for you to battle 'people' you have not got on your friend's list. This however is done through the uploading and downloading of teams. In the Wi-Fi Room of the Battle Tower, you are given the opportunity to upload your own team to the Pokémon Servers. You can then download 7 random teams to battle inside the Battle Tower's WiFi room. These are the teams that people have uploaded, but they're actually controlled by the computer. Although this is nothing like the Random Battles seen in Battle Revolution, it is a good place to start.

The Global Trade Center is likely to be the most commonly used WiFi feature. This building, placed in Jubilife City, allows for you to search for any Pokémon and trade that Pokémon instantaneously. There is one catch, you have to have seen the Pokémon yourself, so unless you have had one, you cannot search for a Bulbasaur or a Darkrai. You are also able to put any Pokémon of yours up for trade and with that, state specific Pokémon that you want in return, at certain genders or levels. A very easy way to trade indeed, saves the time of going onto message boards to do it.