Additional Info
Source: Achievements – Boarding Party
Trophy: Storm Squad (Master) SWTOR decoration, screenshots and information!
Hook: Wall Medium (Blue Square): The Trophy: Storm Squad (Master) decoration fits into a blue medium square wall hook.
Hook: Wall Large (Purple Rectangle): The Trophy: Storm Squad (Master) decoration fits into a large purple rectangle wall hook.
Flashpoint trophies are earned by defeating bosses in Flashpoints on different modes. Some only require you defeat the boss once, others require you to defeat that boss or the whole Flashpoint 25 times.
You can check your progress in your Achievements in the Flashpoint section under the Flashpoint for that trophy.
Source: Achievements – Boarding Party