Aground

You get this achievement once you reach Earth. You will notice some dark colored ruined structures on the surface, some are just below the water line. Although they can be hard to see, there are entrances that take you underground. You will fight some enemy drones throughout the maze and encounter large doors that lead to a tunnel and small doors that require a key card. When you enter the long tunnel with gray blocks at the top and bottom, you need to reach either the far left or far right ends and search the chests for a ruined key card. If you have the amethyst queen drill, you can go through the grey blocks to avoid the obstructions. Otherwise you will have to navigate through more “rooms” to enter the tunnel farther along. There are two total key cards in the maze, but you only need one for the achievement. When you first find them they will be ruined and won’t work for anything.
Proceed back to the left or right from the key chest and keep entering the tunnel doors until you get to a room with a large factory in the center. I believe the door you need has a healing robot outside of it. From the factory, travel straight up through a single block until you see an NPC known as the scavenger. He will give you a quest to get him a keycard, which you already found, so just click him again to complete the quest. The keycard just opens up the locked doors and provides you a shortcut back to the surface. If you found both cards, click him again after you clear the quest and he will also repair the second card, giving you another shortcut.
He will now say something about shutting off the drones and making your own. Go back down to the factory and to the left is a console with a monitor. Interact with this and it will say that you have made all of the drones friendly and the achievement will unlock. I don’t know if you can interact with the console prior to doing the keycard quest, so feel free to give it a try. I will try to update if someone can confirm in the comments.

If something is unclear please let me know.