CSSE120 – Introduction to Software Development (Robotics sections)
Resources for Graphics in Python
The best reference for ttk/tkinter is this tutorial by TkDocs.
It documents Tk, which is a toolkit for several languages, not just Python.
In the Tutorial, focus just on the Python examples, ignoring the examples from other languages.
The classic reference on Tkinter (NOT ttk) is this old and incomplete
Introduction to Tkinter
by Fredrik Lundh. Its information is perhaps easier to understand than the more complete references above.