Sukkot, which begins on the fifth day after Yom Kippur and lasts seven days, is the celebration of the Jews escape from Egypt and their survival during forty years of travel in the desert. They survived in all sorts of temporary dwellings.
And according to Chabad.org, “ever since, we remember G-d’s kindness and reaffirm our trust in His providence by dwelling in a sukkah–a hut of temporary construction with a roof covering of branches–for the duration of the Sukkot festival.”
In addition to Chabad.org, My Learning Learning reviews the basics on a page called Sukkot 101. The International Business Times outlines five things you need to know about the holiday int his excellent article.