You can go with a whole chicken (in Asia, remove the head and feet first if desired), in the US, remove the giblet pack, save those for a snack later. Now you can boil the chicken whole, or you can cut it into the standard pieces or I will just go with two breasts and two quarters (separated), no need for the wings or back.
In a large pot, add the water, onion, lemongrass, and salt and bring to a boil.
Once boiling, carefully lower in the chicken, using pieces would be much easier than a whole chicken. Return to a gentle boil and cook the chicken through (you are making the broth). Chicken cooking on the left, quail eggs cooking on the right.
While the chicken is cooking, open and drain the drain the eggs if using canned, or hard boil them if using fresh, shortcut for hard boiled is Recipe Notes. Prep the pork balls by simply slicing each in half. And then measure out the dry macaroni.
When the chicken is fully cooked, carefully remove the chicken and the lemongrass bundle from the pot. Then add the dry macaroni and let that cook.
While the macaroni is cooking, use two forks and shred the chicken, removing skin, bones, and any gristle, good snack for your dog.
When the macaroni is tender, add the chicken, eggs, pork balls, spring onion, and cilantro to the pot, reduce heat to a simmer and use the Seasonings as listed to taste. Let this simmer for about 10 minutes.
Ladle soup into bowls and use the Garnishes listed as you desire to taste. Serve.