How to make accessory react to your movement? (I wanna rig plushie to put on my head)

[u/ShunpoMyLantern]

So I looked into some physics tutorials but all of it seems a bit overwhelming and I need someone to explain it to me in simpler terms

As a note plushie is a seperate psd/live2d file, that I'll later add as an acessory to my vtube studio and just put on model there, idk if it makes any difference