There are actually more than five swing states. Some people would say there are eleven swing states. However, I can still guide you with your question.
The swing states are critical in this election. Because it is known that certain states will definitely vote Republican or Democratic, the candidates must win enough of the swing states to get to the 270 electoral votes needed to win the election. It is these swing states that will decide if Hillary Clinton or Donald Trump will win the election. As a result, the candidates and their supporters will spend a lot of time and resources in these states. There isn’t much of a reason to spend time in a state that will almost certainly vote either for the Republican or for the Democratic candidate.
As a result, expect the candidates to spend a lot of time in Ohio, Pennsylvania, Florida, North Carolina, Virginia, Colorado, New Hampshire, Michigan, Wisconsin, Iowa, and Nevada. The candidate that wins most of these states will most likely become the next President of the United States.