The Pathless’ textile workshop puzzle is an optional side mission to complete. It isn’t vital in order to complete the main camapign, but trophy collectors will need to do so to earn themselves one of The Pathless’ bronze prizes.
The textile workshop is located in the Sauro chapter, and you will need to use your spririt mask to find it. If it helps, the building in the image above is what you’re looking for, so take flight to aid your quest in locating it. Once you are there, head inside.
You will see a lit torch before you, and an unlit one behind it. Shoot an arrow through the flame to ignite the unlit torch. Fly up to your right and use the lit torch to ignite two that are below you. This will activate two lights on a door and open a gate. Drop down into that side room.
You will see a couple of mirrors, a lit torch and some unlit ones. One of the unlit torches is in the center of the room surrounded by two grates. Press the lever nearby to swing it around. Head into the back of the room and shoot an arrow through the lit torch. Bounce it off the mirror to light the central one. Press the lever again to swing the torch back to its starting position.
Look for a movable mirror. Command your falcon to drag it right next to another mirror. Loose an arrow through the central lit torch to bounce it off the two mirrors onto another unlit one. Now, tell your falcon to move the mirror down its track to the other side. Head around to the torch you just ignited, and bounce an arrow through it and the two mirrors to light the final torch. Grab the block behind the gate that unlocks and place it on one of the pressure pads in the main room.
Walk behind the main room’s central torch and ignire an unlit one above you. Fly up to the first floor again and head into the room opposite to the one you were previously in. Drag another movable mirror along its track until it is facing the doorway. Head back to the torch that you have ignited. Fire an arrow through it and bounce it off the mirror to light another torch.
Grab the block on the pressure pad in the doorway. Carry it to a pad next to you to unlock a gate with the final unlit torch behind it. Move the mirror to the opposite end of its track. Bounce an arrow off the two mirrors, after sending it through the lit torch, to get access to another block. Carry it downstairs and place it on the second pressure pad to open the door. Climb the rope inside this room and grab the crystal above you. You will earn your bronze trophy and be on your way to another falcon flap.