This depends on the pig's stomach you purchased. The one we bought here had already been cleaned pretty well, so all we need to do was to rub the stomach with some fresh lime and then trim off some extra visible fat
Boil the pig's stomach in a water for 1-2 hours or until it is soft. It will still be rather chewy but it should not be tough. You can poke the stomach with fork to see if it is cooked through. If you can poke through, it is done. Discard the water and set aside
Slice the pig's stomach into bite size
Preheat your wok/pan. Add in sesame oil and ginger. Saute until the ginger is crispy, add in the garlic and continue to saute until fragrant
Add in the pig's stomach and the rest of the seasoning (except for water). Saute for about 2-3 minutes. Add in about 1 C of water. Lower the heat and let it simmer until the liquid is slightly reduced. Turn off heat and ready to serve