Activating Gecko Codes In Dolphin

Load your ISO in Dolphin Emulator, via Config Paths. Load the folder that your ISO is in.
Refresh Dolphin
Right click on your ISO file and scroll to the bottom to Properties. Click it.
Go to the directory entitled Gecko Codes and scroll to the bottom of that page and click Download Codes Wiird Database
Your region settings will be taken a copy of the codes of that game from your region will be generated.
Check the little box on the left of each codes for the ones you want to be activated. You must reload your ISO. In other words, Don't use savestates and expect the codes to work. Reload License - Single Player - Time Trials - Character Select - Vehicle Select - Transmission Select - Cup Select - Course Select.

Welcome to TASing with Gecko Codes!