As you venture through the Quarantine Zone in Half-Life: Alyx, you will eventually come to the games’ first real puzzle. A metal barrier will block your path, and you will need to figure out how to move it.
A panel with 16 buttons will be in front of you, and you will need to press the right ones to make the heavy metal door that is blocking your progress open.
If you look to the right of the panel, you will notice a strangely lit area under a bridge, with all manner of designs and lights on the wall. This is actually where your clues lie, and there is a very easy way to find out what to do.
Right beside the panel of buttons, you will see a cage. Open the cage, and all the trash inside will get sucked into a strange energy vortex under the bridge, forming a floating eye on the air. This is one of your earliest introductions to the strange alien magic that is present in some parts of the game’s world.
If you jump up onto the cage and look through the eye, you will see the solution to the puzzle.
Go back to the panel, and push in the third button on the top row, and the second button on the bottom row. That’s it! The heavy metal barrier will be lifted into the air and you can progress further into the quarantine zone.