On day one of the battle the union troops were holding Gettysburg. The confederates attacked Gettysburg and the union troops could not hold them off so they were forced to retreat and when they retreated they created a fish hook on the high ground so that they could not be surrounded.
Day 2
On the second day of the battle July 2nd the union troops held there line in the shape of a fish hook and on a series of hills the confederates decided to attack toward the end of the line so that they could surround them but the confederates failed and were forced to retreat.
Day 3
On day 3 July 3rd the confederates were running low on people and ammo they decided to attack one last time. They failed and lost many man and were forced to retreat. this was the turning point in the war.