How do I make the functions that can be selected in the AnimationEvent popup window?

I'm new to Unity and programming in general, forgive me if the question is noobish :). I'm trying to use an AnimationEvent to trigger another animation. After finding out how to copy my imported animation to avoid the read-only limitations, I placed an event in the desired animation. However, the AnimationEventPopup dropdown menu does not have any functions listed in it.

Is there a way to declare that a script is a function for use in an AnimationEvent? Or is there another way to write a custom function other than scripting?

Any public functions in scripts attached to the same GameObject that the Animation component is attached to should show up, provided that the function argument is of one of the supported types.