What did all the people do when the foundation of the new temple was laid?

Answer: Gave a great shout of praise

With priests' trumpets and Levites' cymbals they sang, "For He is good," and all the people gave a great shout of praise to the LORD.

“When the builders had laid the foundation of the temple of the LORD, the priests in their apparel with trumpets, and the Levites (the sons of Asaph) with cymbals, took their positions to praise the LORD, as David king of Israel had prescribed.”— Ezra 3:10 (BSB)