Instructions
Insert a "Guitar Hero" game into your Wii and start the game. Note that most "Guitar Hero" games, such as "Guitar Hero 3," "Band Hero" and "Guitar Hero: Metallica," do not support custom songs, so make sure to check the game manual of your "Guitar Hero" game to see if it supports the feature.
Pick the "Music Studio" option in the game's main menu.
Use your cursor to highlight and select the "GHTunes" item in the "Music Studio" menu. Selecting this option will automatically connect your Wii to a broadband Internet connection as long as an Ethernet cable is plugged into the back of your Nintendo Wii.
Find custom songs that you would like to download and click the "Download" option for each song that you want to add to your Nintendo Wii. You can sort the available songs using various criteria such as ratings, popularity and when the songs were published. Once you press the "Download" button, the custom songs are immediately added to your Wii.