S.H.
You need "Oyster Sauce."
It comes in a bottle. Asian aisle of the grocery store.
This is how Cantonese foods are made, very often and or other Asian dishes.
Or just look for a stir fry recipe online.
There are many ways to make it.
Or, with "Shoyu" (soy sauce), and Sesame Oil.
Chinese food and Thai or Japanese or Vietnamese or Korean foods, all use different ingredients for "stir fry."