Picture. I don't want deep fry — deep frying wastes too much oil! I just coat oyster with flour, then pan fry like this — way less oil.
But if I want add beer or wine, when?
Do I dip breaded oyster in beer or wine, before putting oyster in pan?
I don't add beer or wine to oil in pan, right?
You should follow your recipe if you have one - for reference, I looked at these: 1, 2, 3.
One recipe specifies quickly poaching your oysters with ginger, spring onion, and a splash of cooking wine, this is an optional step but may remove some fishiness (or 腥味) from the oysters. Next, dredge your oysters in cornstarch (you could also use potato starch) and fry. The listed recipes all pan-fry but you could deep-fry.
The sauce/glaze: fry shallots/red onion with garlic, then add your port wine, some soy sauce, oyster sauce (could substitute hoisin), and sugar. Reduce the sauce then either pour it over your oysters to put them in the oven or toss them together in the pan. It looks like the restaurant does the latter. They may also blend the aromatics into the sauce then reduce it further, remove them after cooking, or just leave them out entirely. None of the recipes mention beer.