How to add a widget/window for user intraction with addon?

Below given is the output of my code and this is the CSS file used by it.
I want to integrate this window into anki for some user interactions.
You can see my whole code here on my GitHub.
The window is displayed by creating a QApplication and integrating it with QWidget inherited class.
So basically, I want a button in menuTools of anki such that whenever the button is pressed this window will pop up and will perform tasks assigned to it.

I pushed the code with some changes on GitHub and it is working fine