Over the course of the game Chadley will give you Battle Intel Reports, more of which will unlock as you clear the ones assigned. Provided you’ve cleared enough of these Battle Intel Reports, in Chapter 8 you’ll unlock your first VR Mission by talking to Chadley, where you’ll be tasked with fighting a simulated battle against a powerful entity - a summon. Defeat any one of these summons: Shiva in Chapter 8 (complete Battle Intel Reports 01-04), Fat Chocobo in Chapter 9 (complete Battle Intel Reports 05-09), Leviathan in Chapter 13 (complete Battle Intel Reports 10-14) or Bahamut in Chapter 14 (complete all other Battle Intel Reports) to earn this trophy. Shiva is arguably the easiest to defeat, and there’s no difficulty requirement for any of these fights. Check out their linked pages for combat strategies.