Head to Tingle Island (C3) and speak with Tingle at the top of the tower. Sensing the Charts in your inventory, Tingle will offer to translate them for you for 398 Rupees per chart.
Once translated, the Triforce Charts can be opened to reveal the locations of the three Triforce Shards. Track down the beam of light that is jetting out of the water in the area that the Triforce Chart reveals and pull up the Shard.