Request:can someone make a way to use custom sims in s4s?

Currently I believe it is not possible to import your sim tray file that you created in Create-A-Sim directly into Sims 4 Studio but you still can customize the default sim model you see in S4S to some extent, here is the tutorial by the almighty orangemittens

sims4studio.com/thread/2056/change-models-appearance-model-viewer