Appearance
Setting up your environment
Rip the game
To start, you will want to buy a copy of Donkey Konga 2 or Donkey Konga 3. Either game will work; however, it is worth noting Donkey Konga 3 released exclusively in Japan and does not have an English localization. After getting a copy of DK2 or DK3, rip the game and have a copy of the rip on your computer. There are a number of ways to rip GameCube games and they are covered extensively in this guide by the Dolphin community.
Load the game on Dolphin
Download and install the latest version of Dolphin. Now you need to point Dolphin to your newly ripped copy of the game. Go to Options > Configuration and select the Paths tab. Under "Game Folders", click "Add", and point to the parent directory where you are storing Donkey Konga 2 or Donkey Konga 3. If done successfully, you should now see the game appear in your library.
Create an extracted copy
Right click the game and go to "Properties". Go to the Filesystem tab in the Properties window and you will be able to see the game's contents. Right-click on "Disc - (Disc Serial Number)", select "Extract Entire Disc", and then choose where you would like to have the fully extracted version of the game.
Load the extracted copy on Dolphin
After Dolphin finishes extracting the game, close the Properties window and reopen the Configuration window. Go to the Paths tab again, remove the path to the ripped ISO, and add the parent directory of the extracted version of the game (i.e. if the game is located in C:/Games/Donkey Konga 2, then point to C:/Games/). Now you have a version of the game that you can easily modify as you add custom songs and scores.
WARNING
Before exporting any tracks, I highly recommend keeping an unmodified backup of SongInfo.res.