Within Star Wars Battlefront there are Challenges that generated by the game to give players extra experience to level up. These challenges will vary from win X amount of matches in a game type or get X amount of kills with this weapon. You can only have three challenges running at any one time. If you are having trouble completing a challenge you can view all the challenges from the main menu and pay 500 Credits to dismiss the challenge for a new one. To unlock this achievement you simply will need to complete 25 of these challenges.