First you need to set up practice codes if you don’t already have them, using this guide. You will need Enable Exit Area Everywhere for this, and FMV Skips is recommended. *If you're using Gecko OS to play a Japanese disc on a non-Japanese console (or vice-versa), you will also need Fix Memory Card Encoding, otherwise Gecko will fail to read the save file.

You may select other codes on the site too, except Fast Any% and Stage Loader as they won't let you visit the airstrip, and Remove Saveboxes as it won't let you save.

Warning: If you already have practice codes, you might have an old version of Infinite Lives which will set your file to 99 lives instead of the normal 3. If the life counter shows 99 upon starting a new file, you should either disable Infinite Lives or download the new version. Likewise Persistent FMV Skips, which is no longer on the site, will allow your file to skip every cutscene instead of just the intro, so you need to turn it off.

Once you have practice codes, start a new file and go get FLUDD.

Right after the cutscene which explains how to use FLUDD, instead of starting to spray the pink Piranha Plant, pause and exit area.

The court cutscene will play, then you will spawn on the plaza. Pause and save, and you now have a hacked file!

The process is similar to how you would make a race file, but because you don’t get any Shine, loading this file will put you on the airstrip.