Duck eggs usually hatch on day 28 but after they pip it can be up to 3 days after the first pip till they hatch so it Is all about patience
If you are getting nervous then you can candle the eggs and look for movement if you see movement leave them be
Good luck
I would read these
https://www.backyardchickens.com/articles/assisting-call-duck-hatches.76507/
https://www.backyardchickens.com/articles/step-by-step-guide-to-assisted-hatching.64660/
https://www.backyardchickens.com/articles/guide-to-assisted-hatching-for-all-poultry.72886/
Good luck