The first chest is literally placed in your way down The second chest is in a hole at the gorgon section. The easiest way to find it would be to turn up the brightness and look to the left a bit and up. you should see it fairly easy, getting there will be difficult the 3rd chest after dying to the gorgons is to your right and follow the path to the right. if you do, you'll come across an open door and it should be upon an elevated platform. I'll try to provide pictures or video once i get the nessecary materials.