I’ll assume you visit the Hunter first. Follow the waypoint to his home in White Orchard – use the green signpost to fast travel there, if you like – then use Witcher Senses to track him into the woods. After a brief chat you can agree to join him to hunt some dogs. The resulting fight is pretty easy; the dogs go down to a single arrow from the Hunter, so if you approach slowly half of them will be dead before you get there.