There are a total of 15 Criptograma Chests and 30 Criptograma Charts in Far Cry 6. Criptograma Chests get marked on the map as you get near it. To open a Criptograma Chest you will need to find 2 Criptograma Charts nearby, which act as keys to open the chest. On opening the chest you will find a Piece of Armor.
You will find blue markings pointing towards the charts. There is also a wind chime near the chest and charts. You can follow the noise of the wind chime to locate them. This article shows the location of Criptograma Chest & Criptograma Charts in the Higado lake in the Sierra Perdida region in El Este.
Higado Lake Criptograma Chest and Criptograma Charts #27 & #07
The Criptograma Chest is north of Higado Lake in the Sierra Perdida region in El Este as shown below.
Criptograma Chart #27: The chart is on the wall of a hut south of the lake as shown below.
Criptograma Chart #07: This chart is inside an enclosure northwest of the previous chart. You will have to destroy the door of the enclosure to go inside it.