Summarize:

Pour 1 Tbsp (15 ml) of vegetable oil into a large skillet or wok. Place the pan on the stove and turn the heat on to medium-high. Let the oil warm up for 1 to 2 minutes. Test the oil by dropping a bead of water into the pan. If the oil is hot enough, the water should sizzle immediately. Add the slices of roast pork and ham to the oil. Place the minced ginger in the oil, as well. Cook for several minutes, stirring frequently, until the meat and ginger turn a light brown on each side. Note that the aroma of the ginger should also become notably stronger. Toss the carrots, celery, and onion into the hot oil. Cook the vegetables, along with the meat and ginger, until the vegetables are tender-crisp and the meat is half-done. Place the bean sprouts in the ban and stir gently until warmed. Remove everything from the pan at this point. Add the remaining 2 Tbsp (30 ml) of vegetable oil to the hot pan. Place the noodles in the pan and cook, stirring constantly, for a full 1 minute.  Use actual chow fun noodles if possible. If not, use any wide, short rice noodle. If you prefer crunchier edges, you can cook the noodles for a little while longer. Do not exceed an additional 1 to 2 minutes, though. Place the meat and vegetables back in the pan. Add the oyster sauce and stir, cooking just long enough to warm the sauce. Note that soy sauce can be used instead of oyster sauce if desired. Garnish the chow fun with chopped green onions and remove the dish from the heat. Serve and enjoy.
Heat the oil. Stir-fry the meat and ginger. Add the other vegetables. Add the bean sprouts. Stir-fry the noodles. Return everything to the pan. Serve.