Four steps, about five minutes. You'll need a Windows PC and your own copy of Mario Kart Wii (PAL / Europe).
Wheel Wizard is the launcher that sets everything up for you.
⬇ Get the latest releaseOn that page, scroll to Assets and click WheelWizardWindows.exe. Open the file once it downloads to install it. (Project home: TeamWheelWizard/WheelWizard)
Open Wheel Wizard, then go to Settings → the Other tab at the top → tick Enable WiiCompiled.
Your Mario Kart Wii file can be any of these formats:
⬇ Get the game file.iso.gcm.gcz.ciso.wbfs.wia.rvzIn Wheel Wizard Settings, find Mario Kart Wii Game File and choose where your file is saved.
Click Play on the Wheel Wizard main menu. Once you're in-game, press F10 to open the settings bar at the top of the screen.