Exactly like you did before.
It’s in the same ‘place’ so to speak. Essentially all Wrath content is in the past now. It’s the same city, but the one in Legion is right now, as the Broken Shore is being flooded with demons from the Tomb of Sargeras. The Dalaran in Wrath is several years ago (Rhonin is still alive, for example). Insert your favorite time travel joke here (my personal favorite is the “You’ve created a time paradox!” clip from Metal Gear, but a lot of you like that “wibbly wobbly” bit from The Doctor.)