You start in a classroom, and need to look at the paper, windows, clock in order to be able to exit the room.
Once in the hallways, Y will bring up a map, and you need to go to the southernmost door (it has an image of a few buildings). Once in the entrance hall, you have to go through dialogues with about 15 different people before you can leave this room.
After that, head to the basketball gym on the north east side of the map. Again, you'll go through a bunch of dialogue and cutscenes before the Prologue ends and the Achievement pops.
You can hold the B button to quickly skip through all dialogue, but even still it took about 15 minutes to reach the end of the Prologue -- if you were to actually read all the text it would probably take a couple of hours.
I could quickly tell this wasn't going to be a game for me, but thought I'd soldier through the Prologue for this first Achievement.