The League's Python Apprentice curriculum introduces students to the core feature of Python using professional tools like Github and Visual Studio Code. The course is aligned with the PCEP™ – Certified Entry-Level Python Programmer exam from the Python Institue, so students who have completed this course will be familiar with all of material on the test.
First, read the Getting Started guide at
https://python-apprentice.jointheleague.org/getting_started.html
Next, after you've started the Codespaces editor, click on the file browser in the left of the window to open the first lesson, which is in the directory:
lessons/lessons/00_Turtles/01_Get_Started.ipynb