Help please!

Im a beginner coder and i just wanted to port something from an fnf mod to my fnf mod and i got this error:
source/FreeplayState.hx:191: characters 4-24 : Type not found : PlayStateChangeables

how do i fix this?

I don’t use HaxeFlixel or FNF, but it looks like you need to install the KadeEngine, which is a mod for FNF and includes the class for PlayStateChangeables. GitHub - KadeDev/Kade-Engine: Kade Engine is a Competitive Rhythm Game engine rewrite for FNF with Quality of Life features included.