To get the hidden Bordeaux, you need to move Ash to various distinct spots on the island. Once in a spot, you need to Jump. These ones aren't that hard to find without a guide. You'll gain 100 Bordeaux for each secret spot.

The Changebook allows you to change the character you control on the island.


This method one is a little more tricky than the Bordeaux, but it shouldn't be too difficult.


Pick up Marona and throw her to the highest point on the house or you can just have her follow you until she's standing on the highest point



Jump on top of Marona but be careful that she doesn't move or else you'll have to move her back to the spot



Jump to the top of the tree to the left of the house in this screenshot

You can still do this at the very beginning of the story.

The first three phantoms you start with will be enough to obtain this secret. Stack and throw all three on top of the giant tree




After receiving the message above, go to Marona and select "Summon"



You'll see the name of the bottlemail phantom class you were given at the bottom. Select that option to summon and the bottlemail will show up.



You should get the achievement now, You'll have 500 extra Bordeaux, the Changebook, and an a bottlemail to use in fights.