In Hogwarts Legacy, the Crossed Wands Dueling Club is an exclusive area for you to unlock. It's not a secret that the students created without the professors' knowledge, but it becomes apparent that it's a well-known secret. Regardless, the professors want the students to practice their spellwork in a secure location, and they allow it.
How to Find the Hogwarts Legacy Crossed Wands Dueling Club Location
After your first Defense Against the Dark Arts class, go to the Dueling Club, which is one of the early courses you may take in Hogwarts Legacy. He'll explain the Dueling Club, and where you can find it. Regardless of whether or not you accept the invitation, your character will need to eventually find this location to complete a handful of assignments given to you by your professors.
How to Get the Kelpie Robe in Hogwarts Legacy
The Crossed Wands Dueling Club will be located in the Clock Tower Courtyard, at the Hogwarts castle's entrance. The closest Floo Flame fast travel point is the Clock Tower Courtyard one, close to the Gryffindor Common Room and the Faculty Tower. The easiest way to get to this point is to start the Defense Against the Dark Arts Classroom.
After reaching the top, go through the first set of doors, where you'll go across a bridge, and then take a left down a hallway, before returning to the top.
Once you climb the stairs, open the first set of doors, and cross the outdoor bridge, the Clock Tower Courtyard will be on the other side.