The History of the Crusader States

From about the year 1000, a confederation of Turkic tribes in the Central Asian step region formed and then invaded Persia or Iran. And so as they conquer much of this region, naturally they displace and subjugate the various peoples who ruled there previously. And then the crusaders arrive. But in many ways, this is a contest between two conquering powers. It's not a contest between one conqueror and then native peoples. The Seljuk Turks perspective because the crusaders threaten their ability to control and dominate the region. How were the crusader states disbanded? And what did this combat look like?