Aloy delves the ruins of U.S. Robot Command to learn more about Project: Zero Dawn. If she can discover the weapons Elisabet Sobeck used to defeat the ancient robot plague. maybe she can wield them herself.
The Grave-Hoard is located at the very end of the map in the North-East. Open the map to check for its location and follow its path. Much like everything else story related, there will be a good amount of Corrupted Machines and Eclipse cultists along the way. Take them out as you encounter them and explore the Grave-Hoard. Scan around for more data points to add to Aloy's notebook.
Along the way you will come across a door that needs to be powered up to open. Keep exploring and you'll find the access modules to its power supply. You will have to listen in on some data points and scan the area for clues to be able to supply power to the door.
One of the geo-therm system reboots can be unlocked by listening to a data point on the ground next to it. Listen for North, East, West and South in the voice log. Point the red portion of the holo lock in the corresponding direction with that exact sequence. The other geo-therm system reboot code is easier, just scan the FARO Code Nexus beside it for the code.
Power to the door should be restored now. Go back and open it.
Upon opening the now powered, unpowered door you will come in to the Armory. Its filled with Eclipse and a Corrupted Scrapper. Kill them to move on into the conference room and access its console.
Continue to explore the Grave-Hoard.
Continue exploring the Grave-Hoard and you'll come into a large hangar bay. This is a boss fight with another Deathbringer but this one is in better condition and can move around. Use the large ammo crates as cover and take out its weapons. Occasionally it will stop moving and go into deploy mode to launch an attack. When it does this, its legs become vulnerable to attacks. Destroy one of its weak points on its legs to temporarily disarm it. Once you've killed the Deathbringer continue on and search around in the War Room.
Once you enter the War Room access the console and listen in on the hologram videos to open the locked door. Go through the door and climb up to start a cut-scene talking to Sylens.
