Green = To Nintendo Wi-Fi Settings / Red = After Access Point Found / Blue = Getting Pal Pad / Purple = Getting Your Friend Code
When you start up your Soul Silver and you're at the Main Menu, you go to "Nintendo Wi-Fi Settings." At this area, you go to "Nintendo Wi-Fi Connection Settings," head to "Connection 1" if you hadn't perform connecting to Nintendo Wi-Fi Connection before, and click on "Search for an Access Point" to let it detect the strongest wireless network like your computer to hook up Nintendo Wi-Fi Connection, highly effective if you're set your DS close to your computer when it's in the middle of searching access point.
After it successfully detected, you go to your computer network and type in the Encryption Key somewhere it's located on the side of your Modem, the Modem is next to your computer that got the connection hook up like DSL, Internet, and Wireless. Encryption Key is a 10-Digit Number to type in, it might be located underneath the Serial Number (SN) and between both the Bar Codes. After you finished typing in, you save the connection setup and start on testing connection. If it's successful, then that means you can finally connect to the internet for Wi-Fi. Click on my rectangular shape signature for more additional materials about setting up your Nintendo Wi-Fi Connection and the text color you're looking for is purple. Here is a video for full visualization.
YouTube - Connecting the nintendo DS to wireless
Now after you got internet connection, you go to your SoulSilver Save File to get your Friend Code. Defeat the 1st Gym Leader name Falkner to get your 1st Badge. After that, you can access to the Bottom Floor of the Pokemon Center and just go down there to let you earn the Pal Pad from the Helper, click Understood if you know everything about Registering Friends.
Lastly, talk to the person of the right door in the Bottom Floor of the Pokemon Center to let her know that you didn't register anyone's Friend Code if you didn't do that and she might be saying you want to register your Friend Code. Accept it and enter Nintendo Wi-Fi Connection to get your Friend Code, if you complete it successfully, move on till you got out of the door and check your Pal Pad.