The first two days (sundown on October 6 until nightfall on October 8 in 2025) of the holiday (one day in Israel) are yom tov, when work is forbidden, candles are lit in the evening, and festive meals are preceded by Kiddush and include challah dipped in honey.
The intermediate days (nightfall on October 8 until sundown on October 13 in 2025) are quasi holidays, known as Chol Hamoed. We dwell in the sukkah and take the Four Kinds every day of Sukkot (except for Shabbat, when we do not take the Four Kinds).
The final two days (sundown on October 13 until nightfall on October 15 in 2025) are a separate holiday (one day in Israel): Shemini Atzeret / Simchat Torah.
Of all the Jewish holidays, Sukkot is the only one whose date does not seem to commemorate a historic event. The Torah refers to it by two names: ChagHaAsif (“the Festival of Ingathering,” or “Harvest Festival”) and Chag HaSukkot (“Festival of Booths”), each expressing a reason for the holiday.
In Israel, crops grow in the winter and are ready for harvest in the late spring. Some of them remain out in the field to dry for a few months and are only ready for harvest in the early fall. Chag HaAsif is a time to express appreciation for this bounty.
The name Chag HaSukkot commemorates the temporary dwellings G‑d made to shelter our ancestors on their way out of Egypt (some say this refers to the miraculous clouds of glory that shielded us from the desert sun, while others say it refers to the tents in which they dwelled for their 40-year trek through the Sinai desert).