If you washed hands, said ha'motzi, and ate some bread in a sukka but forgot to say the blessing leisheiv ba'sukka, you may still say that blessing until you have finished your meal; but you should eat at least 1.3 fl. oz. (39 ml, or 1/6 cup) more of bread (within 4 minutes) after saying leisheiv ba'sukka.
 

When you sit down in a sukka, only say the blessing leisheiv ba'sukka:

• If you are going to eat at least 1.9 fl. oz. (56 ml, or about 1/4 - 1/5 cup) of bread or mezonot within four minutes, OR
• Immediately after saying kiddush and before drinking the wine in anticipation of eating mezonot or bread, OR
• Before eating any food or beverage (except salt or water) when visiting any other person in his/her sukka.

First Night: Say she'hecheyanu after saying leisheiv ba'sukka (in kiddush), since she'hecheyanu covers the sukka and the Jewish festival. 
Second Night: Say she'hecheyanu before leisheiv ba'sukka (since it only covers the Jewish festival itself).

If you sleep at another person's house or sukka during Sukkot, you should consider their sukka as being yours. You do not say the blessing leisheiv ba'sukka except if you eat bread or mezonot there.

• Ma'ariv on both nights of Sukkot may be said from 1 1/4 hours before sunset.
• Kiddush in the sukka may not be said until after dark on both nights.

 

Sukkot means “huts.” The Jewish festival of Sukkot celebrates and commemorates the shelters in which the Israelites lived for 40 years after leaving Egypt.
 
Symbols
The main symbols associated with Sukkot are living in a sukka (eating and, when possible, sleeping in the sukka) and the lulav and etrog.
 
Sukkot is observed at fall harvest time.  When many Jews were feeling wealthy due to their produce, we were commanded to live in temporary shelters--in part, to ward off feelings of arrogance or pride in what we had accomplished in the material world. Instead of thinking or feeling that our hard work or great wisdom has made us wealthy, we are reminded that whatever we have comes from God, and that God will take care of us, even in a flimsy “house.”
 
The lulav and etrog have many meanings.  Here are two:
 
Likening to the Human Body
The four components are compared to four parts of the human body:

• Palm branch: Spine.
• Myrtle leaves: Human eyes.
• Willow leaves: Human lips.
• Etrog: Human heart.

When we hold the four parts of the lulav/etrog together, we are symbolically taking the various components of our bodies together to serve God.
 
Likening to Types of Jews
The four components are likened to four types of Jews:

• Etrog smells nice and tastes nice--like a tzadik who is knowledgeable in Torah and does mitzvot;
• Myrtle smells nice but does not have a good taste--like a person who does mitzvot but is not knowledgeable in Torah;
• Palm tree (date palm) has a nice tasting fruit but no scent--like someone who has knowledge but lacks mitzvot;
• Willow does not smell nice nor has a good taste--like a person who has neither.

By holding them together, we show that all types of Jews are to be consider as one nation.

You do not need to buy a fancy or expensive lulav and etrog if the first day of Sukkot is Shabbat, since the Torah requirement for the etrog to be beautiful is only on the first day of Sukkot.

A Jew may fix or build a sukka on chol ha'moed.
A non-Jew may fix or build a sukka on chol ha'moed or even on the Jewish festival days. A Jew may explicitly tell the non-Jew how to accomplish the repairs or the building of the sukka.
 

In Eretz Yisrael, read only the line for the actual (correct) day.

Since two days of Jewish festival are observed outside of Eretz Yisrael, read the lines for the sacrifice for both days that might have been the correct day.

In the amida of musaf for Sukkot, there is a different line added about the sacrifices for each day.

Except for first night of Sukkot (and also the second night outside of Eretz Yisrael), there is no need to be discomforted at all by rain, cold, or heat. You may eat even bread outside of the sukka without waiting to see if the conditions will become more comfortable. This includes on  Shabbat.

The intermediate days of Passover and Sukkot (between the first and last days, which are festival days) are called “chol ha'moed.”  Passover has four chol ha'moed  days outside of Eretz Yisrael and five days in Eretz Yisrael. Sukkot has five chol ha'moed days outside of Israel and six inside Eretz Yisrael.
The restrictions that apply to the Jewish festival days generally do not apply to the chol ha'moed days (see below for exceptions).

Rain on the first night of Sukkot is only considered a bad omen in Eretz Yisrael.
Reason It does not normally rain there at that time of year.
 

You may borrow a lulav on all days of Sukkot except the first day (or first two days outside of Eretz Yisrael). On the first (two) day(s), you may acquire a lulav and etrog by having a friend “give” them to you as a gift, even if you will later “give” them back to your friend, also as a gift.
Note If you intended to use someone else's lulav on the first day of Sukkot, it is considered as if the lulav is yours, even without doing the normal acquisition.