How do you start the Assassin's Creed 2 DLC?

To start the DLC for Assassin's Creed II, titled "Battle of Forli" or "Bonfire of the Vanities," you need to have completed the main story up to a certain point. Once you have the required memory sequence unlocked, the DLC will become available in the game's main menu, allowing you to download and access the new missions. After downloading, simply select the DLC from the menu to jump into the new content.