In Lexington, the British burnt a building down while looking for guns and ammo that the colonist hide, when Paul Revere showed up and saw them. After he saw them the British started to march toward him to go to concord to search.
As the British came marching, Paul Revere went on horse back telling everyone that the British were coming, so they could get ready for battle.
"The British are coming!" (That is not what he said, but we do not know what he said.)
As they all met, they got ready to attack. The British didn't know what they were in for, and the colonist were ready for anything.
The British were the first to shoot.
It is claimed that the British shot first, people don't know what caused it, if it was an accident or if they were told to shoot, but what we do know is that colonist won that battle and later on, the war.