While playing the tutorial, you'll come to a room with entrances to the north, east, and west. Head into the west door and keep going until you reach the last room on that path. Once you've cleared the room, use a blank to open a secret room. Don't worry if you're out of blanks for some reason; clearing that room will give you one. Collect the shield and helm in that room (you might need to read the note too, but I can't confirm that) and finish the tutorial.
Next time you get to the Third Chamber, you'll find a room with an NPC (it usually branches off of the room with the mine cart puzzle). This is
*** Spoiler - click to reveal ***Blockner. Talk to him and answer with "You know why I'm here." When he asks if you're here to kill your Past, tell him "Manny says hi." He'll retreat into another room. Follow him, defeat him, and you'll earn this trophy. He's not an easy fight, but what in this game is? Try to take out his guards first, it'll make things easier.