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Ok. First you need one of the patch templates from the Riivolution website
here.
Theres the regular one where you have to move all the files from your pf folder to a folder on the root of your sd called SSBB.
The replacement code support one is for people who are used to using the File Replacement codes and therefore you don't need to change your folder setup.
Once you've chosen the Patch Template XML you want to use, you place the .xml in the riivolution folder on the root of your SD.
When you start Riivolution, you should see an option available that you can "disable" or "enable." Select enable and then launch the game and it should work.
Hope that clears things up.