Select it and then receive gift. Get via wireless will allow you to get gifts from stores (e.g. Toys 'R' Us) during their special events, when you are near the store. Get via Nintendo WFC requires the Internet, but gives gifts from there, the Internet. At the moment you can download Oak's Letter via the Internet option in the US, Europe, Australia, etc.
It should tell you whether it was successful or not.
It should tell you whether it was successful or not.