Now that you’ve got the override, it’s time to test it out. Follow your waypoint to the Strider herd, sneak up on one and override it.
Overriding machines will have different effects depending on the type. With herbivores like Striders and Chargers, it will mean you can ride them like a mount. With more aggressive types, it will convert them to fight by your side for a short time. At the moment though, you’ll have a newly converted Strider mount. Have a ride around to get a feel for the controls, then when you’re ready, follow your waypoint and talk to Varl at the gate. There’ll be a cutscene, and a conversation with Varl, then you’ll be able to move on. He’ll also give you The War Chief’s Trail side quest. Once that’s done, head for Mother’s Crown where you’ll talk to Marea.
She’ll tell you to head for Daytower, the Carja fort at the edge of Nora lands, but to get inside it, you’ll have to clear two Corrupted Zones. Corrupted Zones are areas where a group of corrupted machines have banded together, and it’s up to you to clear them out. You’ll see them marked on your map as Xs with a circle around them. Obviously they’re more tricky than regular machine areas, but if you use a few tried and tested tactics you shouldn’t have too much trouble. There are a few of these corrupted sites scattered around the area, and they’ll helpfully have a recommended level on them (although if you’re a skilled player you should be able to tackle them if you’re underleveled). Best practice is to head for which ever site you’ve picked, use your Focus to scout out what type of machines are there then adjust your engagement plans to match.
Once the zones are clear, it’s time to head to the fort. Follow the road there, either on foot or on a mount if you have one. Once you get to the fort itself, you’ll be confronted by a Corrupter and a few corrupted machines attacking the fort. The same rules of engagement with the corrupter still apply, and remember that you can set it on fire to force it to expose its inner, highly damaging weakpoint.
Once it and the other machines are down, talk to the Carja guard to be allowed into the fort, then speak to him again to complete this quest.