A Soldier’s March

Go to the Start of the Climb: Head to the location marked on your map. You'll find two soldiers, one of whom is concerned about her brother attempting a climb as a test of his soldiering skills. She'll ask Aloy to go find him.

Climb Up the Cliff: Once you accept the quest, use your R3 scanner to find the climbing ledges and begin your ascent. It's a fairly straightforward path upwards. When you reach the top, speak with Wekatta.

Kill the Machine: Continue along the path until you find a climber being attacked by a Stalker. Defeat the Stalker to help him. He'll insist on continuing his climb.

Scan for Tracks: Now, you need to scan the area for Penttoh's tracks. Following these tracks will lead you directly up his climbing path. Keep an eye on the tracks; they're usually easy to spot.

Navigate the Climb: At some point, the direct path up the cliff will end. When this happens, look for an alternative route. You'll need to climb up a wall, then use your Pullcaster to grab onto a climbing hook. From there, glide to a ledge on the other side to continue.

Kill the Machines: You'll soon find Penttoh in trouble again, this time being attacked by multiple machines. Help him out. After you've dealt with the threats, he'll want to keep climbing, so follow him.

Climb the Mountain: The majority of this climb is pretty standard. Don't forget to use your Pullcaster if you get stuck or forget it's an option – it's been a little while since it was essential. This part of the climb shouldn't give you too much trouble.

Kill the Frostclaw and Finish the Mission: The final challenge is a tough one: a Frostclaw. Defeat this powerful machine. After the fight, you'll need to head back down to talk to Wekatta to complete the errand. The glide down offers a nice, easy way back to the quest giver.