What did John Locke say about human nature? According to Locke, how did people live in a “state of nature?” What role did Locke believe the government should play in the lives of its citizens?

John Locke's ideas of human nature actually did not differ much in their main premise from those of Thomas Hobbes. Both philosophers believed that human nature permits individuals to act in ways that are essentially selfish. In a state of nature, anyone can harm anyone else, whenever and however it suits them. Someone's power is dictated by their strength and intelligence. Locke believed that a state of nature exists whenever people have no authority that they can turn to for managing disputes. Unlike Hobbes, though, Locke believed that, in a state of nature, people also have the capacity for cooperation and the ability to work toward a common goal.
According to Locke's ideas, as posited in his Second Treatise on Government, the role of a government is to provide a population with a common collective entity for their protection. People voluntarily, although usually tacitly, make a social contract with the government in order to allow for conflict resolution in a process that is more equitable than what would occur in a state of nature. Therefore, a government's role is to fulfill the wishes of the people by enforcing laws that protect the natural rights of individuals (life, liberty, and property) that would otherwise be in jeopardy in a state of nature. The important point that Locke repeatedly stresses, though, is that a government only possesses legitimacy if it operates with the consent of those it governs.
https://plato.stanford.edu/entries/locke-political/