A Warm Welcome
After getting of the boat, speak with Yusuf. Follow him through the city but try to stay close to him. He will give you some background about the city as well as tell you things that might help you, like how the Ottoman soldiers can keep Byzantines off your back. You'll eventually get in a fight with three soldiers and then three more will be chased off by the Ottoman soldiers. Follow Yusuf a little more and you'll finish this mission.
Upgrade and Explore
This mission starts by going in the building by Yusuf. Exit the HQ and head to the Blacksmith. The new armor will cost you 343 so if you don't have enough, pickpocket a few passerby but make sure you keep walking away from them as soon as you do or they may turn around and attack you when they notice their money is missing. Return to the Assassin HQ.
The Hookblade
For the most part, just follow Yusuf through the streets and do as he tells you. To use the extended reach during a jump, hold the grab button in mid-air. To do the long jump, do the same as you pass by a hanging lamp that you would otherwise use to swing around the corner. The last trick, the hook and run, involves holding down the grab button as you sprint at a standing target. Just make sure you successfully do all three for full synchronization.
The View from Galata
Follow Yusuf up to the top of the tower. The important thing here is mastering the Hookblade sling. Make sure you have the camera facing the wall and you are pressing forward as you climb. When you jump for a ledge, as you reach for the ledge, hit the jump button to have the hookblade throw you upward. In cases where there are more ledges above that you can reach, you can continue to hit the jump button to keeping throwing yourself upward. Make it to the top in under 60 seconds for full synchronization. This may take an attempt or two because there isn't really any trick except for a little bit of practice.
Advanced Tactics
Learn how to use the zipline. Follow Yusuf up to the rooftops and then jump on the ziplines. You merely have to run at a zipline to use it so run at this one and the next one to get moving. The last zipline will be used for an assassination. Wait for Yusuf to set it up for you and then zipline down and wait for the "assassinate" command to appear in the upper right, then hit the strike button. Full Synchronization. Now just continue through the city to the waypoint and meet up with the Assassins there to finish the mission.
On the Defense
This is the Den Defense mode. The beginning will set up how everything works. Place crossbows on the roofs until you gain access to the riflemen and place them anywhere you can. Also, once you are told how to use the cannons, use them as much as possible. One shot can wipe out an entire wave of Templars and save you moral. You are graded at the end based on how many Assassins you lose and how much moral you have left over and using the cannons can save you on both. However, aside from that, saving moral doesn't do anything for you so if you are risking losing to save moral, don't.
Just be careful of the last wave because they will bring a war machine with them. Use the cannons on it but your rifflemen will help with this quite a bit. Once you've defended the Den, head towards the docks and catch a ferry.
On the Attack
When you get off the ferry, Yusuf will ask you to join the fray. Kill the three Byzantines here and then follow Yusuf through the streets. He will teach you how to use the new bombs. Do as he says and follow him. Eventually you will get your chance to try the bombs. You'll be told exactly how to do it and where to throw it.
Once you get to the Byzantine tower, Yusuf will distract the enemy and you will have to kill the captain. Yusuf will prompt you to use your Eagle Vision to figure out which guard is the captain. Out of the line up of four, it is the second from the left. Scan him to save yourself some time. Then follow him over the roof tops but don't kill anybody. Just get above the captain and you can do a double air assassination on him and his companion.
Kill him and then head towards the tower. Now you need to climb the tower and light the fire. Just be careful because there may be enemies shooting at you, in which case, try to circle the tower to break their line of sight. Light the fire at the top to end the sequence.
