Sukkot and Harvest festival are similar events, thanksgiving for the harvest. Sukkot is a lot more than that but includes the harvest element.
Sukkot 9 – 16 October, or the Feast of the Tabernacles, is the Jewish festival and a huge part of the celebration is living in a Sukkah, hut, or tabernacle for one week.
“Sukkot is one of the festivals of celebrated by Jews around the world each year. The festival lasts for 1 week and gives thanks for a successful harvest. A key part of Sukkot is the sukkah – a temporary dwelling that each family constructs and in which they will spend time during the festival. The sukkah is a reminder of the Exodus and the dwellings made by Moses and his people during 40 years in the wilderness.” During the festival, meals are taken inside the sukkah, and many people also choose to sleep there.”
BBC Bitesize gives a whole school assembly video with questions: https://www.bbc.co.uk/teach/school-radio/assemblies-ks1-ks2-sukkot/z2827yc
Building miniature sukkahs is a fun activity that could be done with any year group studying Judaism, or just touching on it as part of the harvest. There are some ideas shared on this page. Basically, the Sukkah needs to have three walls, and a roof made of vegetation that one can see the sky through.
Hamilton-Trust shares a KS1 lesson plan covering both Sukkot and Harvest festival.
Twinkl has lots of resources if you are a subscriber.
A real sukkah built by someone to remind them of the simple life they once led.