Introduction to Jewish Festival "Eating a Meal" Requirements

We are required to eat two meals on Jewish festivals, each preceded by kiddush, one in the evening and one in the morning. For both meals for each Jewish festival day (and all three meals on Shabbat), say ha'motzi over two complete loaves of bread, each of which is at least 1.3 fl. oz. in volume. 
Note Girls and women are not required to eat any meals (that is, including bread or matza) on Jewish festivals except the Passover seder. However, if a woman, or girl at least bat mitzva age, wants to eat bread, she should use two loaves, just as men do. This is halacha, not a custom. Also, girls and women may not fast on any festival day so even if they do not eat bread or matza, they must eat some food.

Source of Saying Jewish Festival Kiddush
Some kiddushes are commanded by the Torah (d'oraita); the others are from Chazal (d'rabanan), as follows:
Kiddush d'Oraita
  • First night of Jewish festivals
  • Night of seventh day of Passover
  • Night of Shmini Atzeret.
Kiddush d'Rabanan
  • First day of Jewish festival
  • Second night of Jewish festival
  • Second day of Jewish festival
  • Seventh day of Passover
  • Eighth night of Passover
  • Eighth day of Passover
  • Shmini Atzeret day
  • Night and day of Simchat Torah.
Source of Jewish Festival Kiddush Location
Saying Jewish festival kiddush at the place where you will eat your meal is a rabbinical (d'rabanan) enactment.
Jewish Festival Kiddush-Meal Quantities: Evening
  • For evening kiddush for a first-night (d'oraita) Jewish festival, a minimum of 4 fl. oz. (119 ml) of wine must be blessed on and at least half must be drunk.
  • For evening kiddush for a second-night (d'rabanan) Jewish festival, a minimum of 3.3 fl. oz. (99 ml) of wine must be blessed on and at least 2.0 fl. oz. must be drunk.
  • For the evening meal, as on the first two Shabbat meals and for all required Jewish festival meals, a minimum of 1.9 fl. oz. (56 ml) of bread must be eaten within four minutes.
Eating Requirements for Jewish Festival Morning Kiddush
There are two separate eating requirements during the daytime. They may be combined (say/hear kiddush and start the main meal right away) but are often done separately (say/hear kiddush and then eat some light foods and beverages; the main meal is eaten later in the day).
Note Since eating and drinking requirements on all morning kiddushes (both Shabbat and Jewish festivals) are d'rabanan, the required beverage amount for morning kiddush is only 3.3 fl. oz. (99 ml) instead of the d'oraita 4 fl. oz. (119 ml) (which is required for kiddushes for Shabbat evening and all first-night Jewish festivals).
  • Morning kiddush requires a halachically legal “meal” with these elements:
    • Blessing on a minimum of 3.3 fl. oz. (99 ml) of wine (or other beverage),
    • Someone's drinking at least half the beverage, followed by
    • Eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of some type of mezonot within four minutes. 
      Note If you drink at least 3.3 fl. oz. (99 ml) of wine within 30 seconds, you do not need to eat mezonot.
      Note You do not need to drink the wine or other kiddush beverage to fulfill “establishing a meal.” You may hear kiddush and then simply eat the required amount of bread or mezonot. This applies to Shabbat or Jewish festivals, evening or morning.
       
  The kiddush “meal” does not have to satiate.
 
  • The real meal (kovei'a se'uda) requires eating at least 1.9 fl. oz. (56 ml) of bread (or matza during Passover!) within four minutes. It must include enough food to satiate. 
    Note You can simultaneously fulfill the requirement to “establish a meal” and to “eat a meal” by eating one (the same) piece of bread.