First chop everything up and have it ready to go because once your wok and oil is hot you just want to throw things in.
I usually start with aromatics, in a wok using a high heat frying oil like veg or sunflower or avocado- so that would be your onions, ginger and garlic. Use a high heat and no more than 30 seconds or it will burn. Keep stirring and tossing.
Then add other veg, cut up all around the same size so strips or bite size - mushrooms, peppers, carrot, etc. keep it moving
Now's also your chance to add any protein, like prawns, tofu, chicken cut into small pieces. Stir and toss lots.
If your noodles aren't cooked, cook them quickly separately and rinse under cold water so they don't stick. They might already be cooked eg if they're in a pouch in which case you can add straight to the wok once the veg is slightly softened and protein cooked.
For the sauce I'd mix the hoisin in a small bowl with some soy, sesame oil and rice vinegar if you have it. Then pour over the food in the wok when you add the noodles.
Finally at the end I'd add the greens just to wilt in the heat of the noodles, and also some sliced spring onions. You can also add coriander if you like it, a squeeze of lime, some crushed peanuts or sesame seeds.