By moving into the Sukka and leaving the safety and security of our solid homes, we are reenacting those glorious days when we were under His “direct protection”, which is ultimately the protection that matters the most.
There are many details and specifications as to how to build the Sukka.
The basic principles are:
WALLS: The walls, usually 3 or 4, must be built first before we place the sekhakh (covering). We could make the walls of any material capable of withstanding an average wind. This is why rabbi Obadia Yosef z”l recommends avoiding fabric for the walls and instructs to use wood or panels instead. See below.
SEKHAKH: We place the ‘sekhakh’ on top of the walls. For the sekhakh we can use all kinds of branches: bamboo branches, leafy branches, palm branches, etc. Special curtains made of reeds or bamboo can also be used for this purpose.
SHADOW vs. RAIN: The sekhakh /covering should be dense enough to provide a shadow that would cover most of the area of the Sukka at noon, but it has to be fragile enough to allow rain to come into the Sukka. An impermeable “hut” is not considered a temporary dwelling and therefore is not a valid Sukka (=pesula).
Most of the Halakhot of building a Sukka are identical for Sephardim and Ashkenazim. See this for a specific rule about the walls, by R. Obadia Yosef z”l.
LIVING IN THE SUKKA
The rabbis explained that to fulfill the Mitsva of dwelling in the Sukka we should leave our primary residence and settle in the Sukka. They said: “For the seven days of the festival, each person should turn the Sukka into his permanent residence and his house into the temporary one”. Living in the Sukka means that all regular activities we do at home should take place in the Sukka.
Some examples:
MEALS: Except when raining, we should have all our meals in the Sukka. According to Jewish Law, all formal meals -which are defined by the recitation of hamotzi and birkat hamazon– must take place in the sukka. That is why when having a formal meal, with bread, we recite the berakha: ….asher kiddeshanu bemitzvotav vetztivanu leesheb basukka.
MEZONOT: Pastries, cakes, cookies, etc. (mezonot) should also be eaten inside the sukka.
SNACKS: A light snack (a fruit, a salad, coffee) might be consumed outside the sukka. The rabbis praised those who, during the festival of Sukkot, would not eat or drink anything outside the Sukka.
SLEEPING: Sleeping in the sukka is part of the Mitsva of “settling” in the sukka. However, the fulfillment of this Mitsva depends on a few factors: weather conditions (cold temperatures and obviously rain); one’s physical condition (health, sensitivity to cold, age, etc.). In some areas, we should also be aware of safety concerns, like the possible presence of animals (raccoons, foxes, mosquitos, or other insects), etc. this could also be considered a factor to be excused from sleeping in the Sukka.
All regular activities we usually do at home, like studying, reading, napping, relaxing, etc., should also be done in the Sukka.