This achievement is very easy and can be gained as soon as you start your story play through.
All you are required to do is find a Discovery Chest and press
on it to open up and receive your coins or and relics to be award your achievement.
There are 3 chests within Apocalypseburg which are in and around the Fallen Statue of Liberty, from where you spawn into the game for your first time. There are plenty of Chests within the game, in all new map locations so don’t worry if you do miss these first few.Locations & Images below:
• Chest 1 behind Grey large Box near Metalbeard (Pirate):
• Chest 2 behind the Large Brown Dome you unlock Lucy from:
• Chest 3 as you climb up the fallen Statue of Liberty:
As soon as you walk upto the chest you will see the
button prompt press, pop achievement unlocked you are 15g richer.