Third Crusade short how to play

About Third Crusade, from BoardGameGeek:

Unite with your brothers in arms for this holy war. Richard Lionheart and the Angevine have joined with knights from The Holy Roman Empire to try and conquer the city of Jerusalem and retake the holy land from Saladin's Ayyubid dynasty and the Turkomans. Fight for control over the cities and deserts of Palestine. Plan out your actions alongside your ally before turning against them and take the victory for yourself. Send out cavalry and siege engines to battle your enemies, but be aware of their need for water. You don't want your army to die of thirst before they even clash with the enemy. -description from the publisher