To lead means to go in front, or to serve as the leader of a group. If you’re on a group hiking trip and the navigator lost the map, you’ll want someone with a good sense of direction to lead the group back to the car.
If you have done excellent, groundbreaking research into cancer treatment, someone might say you lead the field in finding a cure for cancer. If we say a football team has a strong lead, that means that they’re on the way to winning a game. If you are a detective and you discover a room full of evidence on a case, that might lead to its solution.