ACCESS THE CRYPT
From the Kuwaq Yaku Base Camp (the first one you find), go forward to the red bridge – you can hop off the bridge and into the river to the left. Swim towards the small shore ahead to find the crypt entrance. You can pick up a survival cache and some salvage before you go inside.
Dive beneath the water and follow the tunnel through to the other side. Just to your right, before you resurface, you can pull some Gold from the wall. Now leave the water to the left and climb the ledge ahead.
Keep going until you come across a barricade – you can burn it down, so do this by either crafting a Molotov or using a fire arrow.
Remember, you can pick resources like cloth and mushrooms along the way.
FIND THE SARCOPHAGUS
As soon as you’re inside the first room, look to your left to find an Archivist Map in the corner. Pick it up to reveal locations of several collectibles on the map.
Continue into the next room to find a mural, then head down the corridor on your right. What’s left of the bridge ahead will collapse, plummeting you down a long slope. Navigate the slope left and right to avoid running Lara through some spikes, then leap off the very end quickly followed by throwing the Grapple Axe to swing across to the far ledge.
Head down the corridor, jump over the gap, and find the sarcophagus in the room at the end.
EXIT THE CRYPT
Once you’ve obtained the VESTIGE: NINE STRIDES’ BOOTS reward, you can turn around to leave.
Head back across the gap and swing from the same hook as before to jam the axes into the craggy wall on the other side. Follow the wall upward to the ledge and stick to the right side path until you have to swing from a second hook.
From here, simply follow the pathway back outside, then head left to pick up some fat and Gold before jumping back into the water.
Swim back through the tunnel until you’re at the entrance again.