The shelters provide the practical purpose of offering shelter from the weather. They also provide a substitute for home, a place where the boys can gather together in the hours of darkness to seek comfort from being close to other people. They provide an escape from the darkness and unknown which lies outside their walls. Symbolically the huts represent the failure of the boys society. Collectively the boys decided that they needed huts, collectively they agreed to put in the work to build them and then they all went off to bathe and play and left Ralph and Simon to get on with the work.
Most commentators feel that the chapter titles Beast from the Water and Beast from Air symbolise Hilter's invasion plans during World War II. I think Huts on the Beach is a symbolic reference to the coastal defenses made by Britain in preparation for the expected invasion by Germany during World War II. The huts foreshadow the coming conflict between Jack's tribe and Ralph's group. As a supposed symbol of unity they fail badly as the majority of the boys took no part in building two of the three shelters. Indeed while Ralph and Simon struggled to build the third shelter most of the other boys were bathing while Jack was off hunting, which caused a good deal of friction between him and Ralph when he returned.
They make three huts.
Water in Lord of the Flies symbolizes rebirth.
adaptation to the island
In chapter three: Huts on the Beach Ralph and Simon are in the process of constructing the third shelter.
lighting will symbolize the death and hardships of the boys and the dangers that they encounter with their surroundings and savage ways.
simon
They make three huts.
me
The title of chapter three in Lord of the Flies is "Huts on the Beach."
Nobody was helping build them
Water in Lord of the Flies symbolizes rebirth.
the men
adaptation to the island
In chapter three: Huts on the Beach Ralph and Simon are in the process of constructing the third shelter.
The savagery inside the boys themselves.
The side of the island where the lagoon faces
I am pretty sure he symbolizes democracy and goodwill.