The beginning of GW2 Rox story occurs in the Black Citadel Command Core. If you’ve never been to the Black Citadel, you can travel through any city to Lion’s Arch, and then take the portal guarded by Adamant Guard charr. The closest waypoint to your destination is the Imperator’s Waypoint. Look for the yellow instance entry icon that reads Rox: Critical Mission when you mouse over. When you enter the Command Core and approach Rox and Rytlock, a short scene will play. Talk to Rox afterwards to earn the associated achievement. Rytlock will send you a mail that explains where to go next.
The second half or Rox’s story occurs at the North Nolan Hatchery. It is located just north of the town of Nolan in Diessa Plateau, just outside the Black Citadel. Take the Diessa Gate waypoint and leave the Black Citadel through this portal. If you open your map, there should be another yellow instance entry icon nearby. Enter the instance, approach Rox and have fun! You can complete Rox’s instance for gold and karma once a day.
Rox Story Achievements: Rox the Hatchery, Hero’s Aid
Rox Story Rewards: gold and 3000 karma
Wooded Kingdom Moons in Super Mario Odyssey