Find a beach, ocean, or snowy beach
Look for a buried treasure map in shipwrecks or ocean ruins
Open the map and locate the red X
Travel to the X on the map
Stand directly over the X
Dig straight down with a shovel or pickaxe
Keep digging until you find the chest
Open the chest to collect the treasure
Use the Heart of the Sea, iron, gold, diamonds, and other loot inside
If you cannot find it, move a few blocks around the X and dig again