First, you need to marinate your beef with 1 clove of minced garlic, 1 teaspoon sugar, teaspoon ground black pepper, 2 teaspoons soy sauce & oyster sauce, and 1 teaspoon of sesame oil. Set it aside or keep it in the fridge.

Cut all the vegetables into stripes and prepare to cook :)

Cook the noodles according to the instruction of the package . You can blanch the spinach at the same time. Bring a large pot of water to a boil and add the spinach and blanch for 30 seconds to 1 minute, rinse the spinach and squeeze it with your hands to remove any excess water then put in a big bowl. Let the water keep boiling to cook the noodles too. when the noodles is cooked put it on the bowl where the spinach is (see picture below). You can add little sesame oil to the noodles so it will not stick together.

On the pan fry the egg (scramble egg) then set it aside and cut it into small stripes

Then on the same pan put little sesame oil and stir-fry the carrot for 20 seconds. Not too cooked it depends (I like my carrot a little crunchy)

After you stir-fry the carrot put it on the same bowl where the noodles and spinach is. (see picture below)

On the same pan put little sesame oil again and stir-fry the remaining vegetables (red bell pepper, mushroom,spring onion) When all the vegetable is cooked, transfer it to the noodle bowl.

On the same pan put little sesame oil again. Add the beef and onion, stir fry it until the beef is no longer pink then transfer it to the noodle bowl. Try taste test on the beef if you are satisfied with the saltiness or sweetness of it. (adjust it depend on your preference taste)

Since the beef is already marinated and seasoned you don't have to add seasoning on it (if you are not satisfied with the taste you can adjust it by adding more oyster sauce on it or salt) Mix all together by hand or spoon.