You unlock this achievement by playing all maps that are part of Death Star DLC. I got this by selecting Death Star DLC playing through once as Rebellion staying in lobby until sides switch to Empire(can be done as Empire to Rebellion as well). DLC is very short and took me no more than 45mins to complete both cycles. You do not need to play Battle Station and Blast separately as maps are the same. Achievement will unlock at the beginning of last needed map.
Death Star DLC maps and game modes are as follows:
FIGHTER SQUADRON - Death Star Surface, Imperial Blockade
BLAST - Defense Sector, Power Sector, Command Sector
BATTLE STATION - Defense Sector, Power Sector, Command Sector
Thank you. Happy Hunting!