What is "The Hero's Journey" in "A Doll's House"?
If you're asking about the steps of the hero's journey, I think you have to look at Nora, who I believe is the heroine of this story. The hero's journey begins with a call to adventure, a refusal, and then a divine guide that helps the hero to embark on his or her journey.
What is Nora called to that threatens her safe, protected way of life? How does she refuse the call? What is the force beyond herself that pushes and helps her to follow the call? What struggles does she encounter along the way? What forces from her past does she have to reckon with? What does she gain in the end? How is she different? If you answer these questions thoughtfully, you'll be well on your way.
You can ask yourself the same questions about Helmer, but I'm not sure that he's on a heroic journey or that he's much different by the end of the play. See what you can find, though!