How did the fighting between the colonists and Britain begin?

The British demanded taxes, the colonists refused to do so. The reason for tax is because the British sent a lot of red coats to protect the colonists from other rival countries of expansion. (especially Spain) The king imposed tariffs on goods such as tea, sugar, and paper. Remember, " No taxation without Representation."

I believe it's because the British were charging the Colonies to much in taxes and the Colonies wanted to be on their own, you like when you go away for college and your parents still try to hover 500 miles away. But the British didn't want that so they began to fight.