He suggests that they should have 2 fires, one on the ground and one on the mountain top so they have a better chance of getting rescued. Also, he wants to make another fire because it will give everyone a sign of hope again.
Piggy suggests building the fire on the beach by using the lenses of the boys' glasses to focus the sunlight and start the fire. He recommends using the lenses like a magnifying glass to create the fire. Eventually, they successfully build the fire on the beach.
The boys use his specs(glasses) to direct the sunlight to the sticks on the mountain and make a fire.
Piggy suggests building a signal fire to increase their chances of being rescued which cheers up Ralph. Piggy also reminds Ralph of their goal to work together and maintain order on the island.
Piggy suggests using his glasses to start a fire by focusing the sunlight, rather than relying on the unreliable matches. He believes this method will be more efficient and effective in ensuring their rescue.
When Jack accused Piggy of not helping much with the building of the fire in chapter2: Fire on the Mountain Simon defended Piggy by mentioning that they had used Piggy's spectacles to light the fire so he had helped in that way.
he says that they could use the materials to start a fire
his glasses
The other two characters who helped keep the fire burning in "Lord of the Flies" were Piggy and Simon. Piggy was responsible for suggesting the idea of using Piggy's glasses to light the fire, while Simon helped to gather wood for the fire.
Ralph wants to get Piggy's specs back and Piggy wanted to kill Jack there and then.
They took Piggy's glasses, and fire from Ralph's camp.
Who suggest Ralph & Piggy should go to the party in Chap.9
It is Jack's idea to use Piggy's glasses to start the fire. Jack steals the glasses right off of Piggy's face without even asking him first.