Overview
"Activate the lock device switch underground" is an objective during the Gate to the Otherworld main quest in Chapter 4 of Crimson Desert. You need to find an underground area, locate a wall panel, and press a sequence of buttons in the correct order. Getting the order wrong is not a problem since the puzzle can be reset at any time.
Finding the Underground Area
From the plaza where the quest objective begins, head to the northeast corner. Follow the path lined with lanterns. It leads underground to the lock device.
Solving the Lock Device Puzzle
Once underground, interact with the wall panel (the "hatch"). The lock device has multiple buttons arranged in a grid pattern. Use D-Pad Left/Right to cycle between which button is selected, then press the interact button to push it.
Press the buttons in this order:
Top-left corner
Bottom-right corner
Bottom-left corner
Top-right corner
Middle
When all five buttons are pressed in the correct sequence, they all glow simultaneously, indicating success.
Resetting the Puzzle
If you press buttons in the wrong order, back away from the wall panel to reset the puzzle. Interact with it again to start over with all buttons in their default state. There is no penalty for incorrect attempts.
After Solving
Interact with the wall panel a second time to use the handle. A cutscene plays showing the underground machine booting up. The next objective is to insert batteries to activate the device back up in the plaza above.