This trophy is earned by performing the necessary actions during specific battles.
During battle you'll see a displayed mark on the screen, indicating a Secret Action is hidden somewhere within the battle. If you manage to identify the action you'll engage in a hidden scene with a button entry challenge.
For identification there are 3 indicators of a Secret Action input:
Emerald Foot- Use chakra dash from a distance
Purple Jutsu Scroll- Use ninjutsu
Golden Sub Log- Use a substitution just before an attack connects
The earliest that this achievement can be earned, and when I earned it, was during the battle of Minato vs Masked Man. I was prompted to chakra dash towards Masked Man during the 2nd half of the battle when the emerald foot appeared. If, for any reason, you aren't able to initiate the Secret Actions no worry. You can retry ANY battles post-story in the Ninja World timeline for another try.