A weight of ~1.0 is recommended (You might want to adjust the weight depending on your model).
Feel free to experiment with other weights and share your results if you want to!
The main prompt is "FernFrieren".
Use "very long hair" for her base hairstyle and "purple eyes, (purple pupils)" for her eyes.
For her outfit add the following prompts:
"white dress, black robe"
Let me know if you have any issues.