This location can be found near Persephone's Akropolis. This is one of the more important locations in Assassin's Creed: Odyssey Fate of Atlantis, as you'll visit it when completing story missions.
To get access to the interior of this area, you need to find a cave entrance. It is characteristic for its size and decorative columns.
The cave does not contain any side paths - run straight ahead until you reach the table.
Unfortunately, there are enemies nearby. Try to get rid of them quietly.
Activate the table once you eliminate the opponents. You've cleared the area. Moreover, if it's the fourth table you've activated, you'll complete the mission.