@Phuket2 thanks for your reply and comments.
I had played a little with tkinter befor trying pythonista. There, I made a frame called root and placed all of my widgets in the root.
When I start to think of parent child relationships at different levels, things are starting to make sense.
I will read up on superview.

Thank you

@dgelessus thank you for you response. My ui is now working.
I don't fully understand how, but I will go back to the tutorial and work it out.
Thank you once again

import ui

def hit_button(sender):
    textfield1.text = 'Hello'


ui.load_view('My UI').present('sheet')

NameError: name 'textfield1' is not defined

I am using Pythonista 3
I have made a pyui file with a button and a label.
In my py file I have a defined a function for button action.
I want the function to change the text in the label.
Now I am stuck, what am I missing?
If you think you can help, thank you 😊