the first or second time

The first time? please help

you need to dig under a tree next to the cliff on the island you just got to then go
through the cave and a map will be revealed im pretty sure but I havent played in a while

Go to Molida Island and dig under the big palm tree,there will be another hideout under
the hole, jump in it.Inside on the wall there's a framed map and it shows how to get out
of the fog,just mark it on your map and your'e ready to go! I hope this helps!