When you start the scenario, send 1/2 of your knights to Bavaria and the other 1/2 to Saxony. Train men at arms at one of your barracks and research long swordsman at the other. Every time a new infantry unit is trained, move him to the Westernmost shallows in Bavaria and the 2 gaps in the trees near Saxony. Those are the easiest ways for Poland to enter your allies' cities, and if you seal the route, your allies will be relatively safe.
Immediately when you start, trade wood for 300 gold at your market. Then research redemption at the monastery. Move all of your land units East, and you will find Crema. Convert the nearest buildings(2 houses and a market), and use 1/2 of your troops to defend against a counter-attack. Order the rest of your troops to move South, and you will encounter troops and villagers(the troops being beside military buildings and the villagers being beside the mill and lumber camp.
When the scenario starts, immediately board all of your units onto your transport ships. Sail your ships North along the river, as you must give up your fort, the enemy troops are far to numerous for you to fight. Cross a shallows, and you will find possess a navy consisting of 4 war galleys, 2 fire ships, 6 fishing ships, and 4 transport ships, with 5 knights, 2 scout cavalry, 3 teutonic knights, 5 villagers, and 5 onagers loaded on the transport ships.
Move one of your siege onagers South-West, until it spots an enemy galleon. Order it to destroy the ship, it will sink it very quickly. Cross the shallows with your pikemen, and soon you will reach a gaia farm and house. Suddenly 4 Saracen Navy mamelukes will appear beside the house any will attack your lightly armed infantry units. Quickly move up to them and kill them.
When you start the scenario, you already will have a castle, so you will have a chance to defend if you are attacked in the start. Immediately wall in the 2 shallows to the South-East & North-East, and the bridges to the North-West & South-West. Train more villagers, and build a stable and train knights, along with building a market. While the market is being built, march your light cavalry North along the East bank of the North-Eastern river on the map.
In the 1st 10 minutes of the scenario you will need to do several things in a small amount amount of time(10 minutes), so set your game speed to "slow"(of you do not have it set there already). Build a seige workshop and research bombard cannon. When the technology is researched, build 2 bombard cannons and take them(with 1 paladin and 2 pikemen) far East to the cliff that holds all of Damascus' houses.