which details in this legend reflect what people ate, what they wore, and how they celbrated?

We are shown the festive scene at King Arthur's castle. There is much food and opulence:

For there the feast was held full fifteen days alike with all the meat and the mirth that men could devise. Such a merry tumult, glorious to hear; joyful din by day, dancing at night. All was high joy in halls and chambers with lords and ladies as pleased them best. With all the weal in the world they dwelt there together, the most famous knights save only Christ, the loveliest ladies that ever had life, and he, the comeliest of kings, who holds the court.

Poor people during this time lived in poverty.