Earn a rank of 5 Stars in the battle with Proto fal'Cie Adam in Episode 4 - You'll encounter him in Augusta Tower AF200. Note that there are actually THREE forms of Proto fal'Cie Adam. If you defeat the 1st and 2nd forms and succeed at the QTEs (which are the requirements for this trophy), you'll never encounter the 3rd form. However, the 3rd form is needed later on for 100% Enemy Report - Intentionally fail at the QTEs to make the 3rd form show up when the time comes for 160 Fragments (Step #2 of the Road Map).
Set battles to Easy Difficulty for a better chance to earn 5 Stars. If you aren't confident in your performance, hit to Pause before the end of the battle and Retry it. You can also return later and attempt the boss battle a second (or third, or fourth) time via a Time Reversal. Remember that in order to do a Time Reversal, you need a Reversal Rock from the area first.