Before being allowed to speak to him, he will ask you to find a "magical flare". Simply claim your firework in SOE station cash under the "summer fireworks festival" section. Then speak to him to get a quest that requires you to launch 10 fireworks. (Click on the fireworks launchers located throughout the city to get an update.) As a reward, you will get a fireworks launcher for your house. Either quest is repeatable; you don't get a different launcher when repeating the quest in the same city, but you will receive a different launcher from coordinators in other cities.