The laws of eating meals on Shabbat are well-known and don't appear to be the core of your question, in any case Kitzur Shulchan Aruch (KSA) 77:16 provides a good overview.
The same KSA in siman 103 provides a number of relevant rules regarding meals on Yom Tov. I picked a number of them but it is good to read the original.
Just as it is a mitzvah to honor the Shabbos and delight in it, so it
is a mitzvah to honor all the Yomim Tovim [...]
What is meant by delight? [...] on each Yom Tov day you must have two
meals, one at night and one during the day, but it is not our custom
to have a third meal. [...] you should be lavish with meat, wine and
sweets, according to your means.
Every man is obligated to gladden the hearts of his wife, his
children, and all who are dependent on him, in a way suitable for each
[...] to the men, meat and wine. It is the custom to serve a greater
variety of foods on Yom Tov than on Shabbos, because with regard to
Yom Tov, the Torah mentions "rejoicing," but it is not mentioned with
regard to Shabbos.
Even though eating and drinking on festivals is a positive
commandment, you should not spend all day eating and drinking [...]
And when you eat and drink, it is your duty to provide also for the
orphan, the widow and other needy people [...]
When a person eats and drinks, and rejoices on the festival, he should
not overindulge in drinking wine, in laughter and lightheadedness,
thinking that the more he indulges, the greater will be the mitzvah of
rejoicing.
KSA doesn't explicitly address meals on Chol Hamoed. R Aharon E. Marcus, in his excellent Halacha 24/7/12, writes (p. 264)
According to most Poskim, you should have a reviit or wine and a
kezayit of meat every single day of Yom Tov, including Chol Hamoed. R Shlomo Zalman Auerbach says that grape juice and poultry qualify as
meat and wine, but R Moshe Feinstein and R Eliashiv say that you
should consume alcoholic wine and beef.
Similarly R Dovid Zucker and R Moshe Francis in their book on the laws of Chol Hamoed p. 21 write
[...] each person should rejoice in the manner most compatible with
his nature. Thus [on Chol Hamoed] according to many authorities, a man should drink a reviis of wine daily (some authorities allow grape juice instead of wine). It is also preferable to eat a kzayis of
meat daily [and it is even permitted for women on their
mikve day] (see there and appendix for sources)
See also here for the views of Shulchan Aruch HaRav.
