And now the Proving starts. For the first part, you have to down a grazer and loot its trophy. Bast will shatter your first trophy so you have no choice but to down a second grazer and loot another trophy. They’ll running around so deploying tripwires along the way will help. Otherwise, if you already have Concentration, you should be able to hit the canisters on their backs even when they’re running. After getting your second trophy, leave the other grazers alone and follow the marker to start the Brave trail.
Sprint and climb over the obstacles until you catch up with the proctor. Since Aloy needs to catch up, she decides to take the hazardous abandoned Brave trail. The trail is very straightforward but you have to watch out for the slips and falls, as well as jumping accidentally to the wrong direction. Keep sprinting and keep your pace up. The trail should be short enough; in the last leg of the trail, you have to cross a narrow wooden beam before ziplining to the finish. Another cutscene will take place and risking your life on the abandoned brave trail gave you the chance to finish first, despite the handicap.
The celebration however, is short-lived since a group of masked invaders will rain down fire arrows to the new braves. You have to fight back so equip your fire arrows and shoot back at the invaders. There are scattered medicinal herbs and supply crates so use them to resupply. Fire arrows are equally damaging to you and against the attackers. Take out the first wave of attackers and a cutscene will trigger.
Another wave of attackers will rush in so you have to heal up and craft more arrows as needed then kill them all. When all the second wave attackers are down, Vala will tell the other young braves to descend. At this moment, the cultist leader will be bringing in a heavy gun and rain down lead. With Aloly the only remaining survivor, she has to deal with the last wave of enemies alone, including the heavy gunner.
Keep moving and keep showering the heavy gunner with fire arrows. The burning damage will keep damaging him and prevent him from using his heavy weapon. If ever he gets the chance to use the weapon, find cover immediately since it can rip you to shreds. Only try to shoot him back when he needs to reload/cool down the weapon. His allies will either shoot from the ledges or charge at you with a melee weapon. After taking out the heavy gunner, you can pick up his weapon and use it against the remaining cultists. Otherwise, you can just pick them all off using your fire arrows. After taking them all out, watch the following scenes and the quest will automatically be complete.