In Napoleons time the bayonet charge was used to try and route the enemy from their position, to turn them making them an easier target. Napoleans army would have fought with Muskets, In the US civil war the introduction of the rifled barrel, like this Springfield, would have improved the accuracy of the shooter and meant that the charging force was at a distinct disadvantage as the stationary defender could pick them off much more effectively. The chance of using a bayonet was limited as you were probably dead before you got close enough to swing. You can see how the men were lined up in long lines in some of the surviving pictures such as the dead at antietam: Once the generals figured this out you began to see troops taking defensive positions behind trees, hills, walls etc.From what I understand both North and South used some tactics gathered from the Native Americans. Is this right?
I haven't heard of this but it could well be true. I think most of the tactics used were pretty close to those of the Napoleonic wars which saw lines of infantry (dressed in bright colours of course, no allowance for camouflage to protect the troops ) firing at one another at short distances. 