The rhymes are supposed to give clues about what's inside. After that, the order varies between different families. We usually put all the food and all the accessories on one table, in bowls and bottles, and the guests who are seated at another table, bring their plates and pick what they want to eat. You can go there as many times you want and collect more, and the meal usually goes on for hours. This is the same but with Christmas related dishes.
Many people hide an almond in the bowl of rice pudding.
Nowadays you can purchase them finished, but traditionally they took days to prepare. The ham is first cured in salt. On the day before Christmas Eve, the ham is boiled for several hours. The ham is then left in the broth overnight in a cold place. On Christmas Eve, the ham is dried, painted with a coating of egg and mustard, sprinkled with bread crums and baked at a high temperature for a short time.