Before someone has the time to come by and give you a more detailed answer here is the sections from the FAQ that deals with this.

https://www.reddit.com/r/AskHistorians/wiki/us_history#wiki_colonial_america

The basic gist is that what you were fed is about 99% romanticized BS, but we don't expect much from elementary school now do we? The major engagements that decided the war were battles fought between armies of line infantry supported by cavalry and artillery depending on the situation and what was available. The reason soldiers marched in tight order and didn't use guerrilla warfare isn't because they were bumbling oafs who didn't know any better but because these were the tactics as dictated by the technology of the time (This is actually a pretty general answer you can apply to most questions you have about why people of the past didn't do X. People from the past were not idiots.) Smooth bore muskets are not very accurate and it would take massed volleys to make them effective and often times battles would be decided with a bayonet charge. Even more important is the defense that organized numbers offers from things like cavalry charges or the aforementioned bayonet charges. Yes there were rifles, but it was not feasible to produce and equip entire armies with them. Yes BOTH sides employed light troops to screen their own forces and harass the enemy but you don't win a war with skirmishers. Remeber, the British had been a colonial power for hundreds of years. They fought the French and Indian wars with the colonials. They didn't turn a blind eye to the native Americans and had already developed their own light infantry.