The garlic frying step seems to be missing

You’re right, it does appear that a step is missing! And yes, since sesame oil is the only oil listed I would assume that the garlic is fried in that oil. For cooking time on the garlic I would go by color. I would cook it until it assumes a light golden color. You want it fragrant but not too dark, as garlic burns easily and can turn very acrid when burnt.