It's clear you need to implement a way to select a file and toggle the auto-populate features of the form. First, you consider just adding controls to the main application for both of these, and make this quick mock-up:
It doesn't take long for you to realize that this is not a great design, and certainly not one that will accommodate growth. Your users don't want to have to type a file path and filename blindly into the box, nor do they want a lot of extra fields cluttering up the UI.
Fortunately, Tkinter offers some tools that will help us to solve these problems:
- File dialogs: Tkinter's filedialog ...
