I'm having trouble connecting to the internet how do i connect to a hotspot?

I am having trouble with connect to the internet . If i go on my Wfi connection settings on my Nintendo ds its always a red or grey icon. This person says i need to type in Action Replay (AP) to get in the house in Cave city but i dont know where to type in. I'm so confused don't know what to do any help will do i want to get the last legendrie on pokemon pearl (sorri i didn't mention that eailer) but don't know how plz help me connect to a hotspot and plz help with connecting to the internet please please i would really appreciate it. Who ever answers it best gets ten points!!!!!!!!!! thank u