I think the best approach would be to start with some demo project.
Just keep increasing the complexity of the project and you'd learn more from selenium and python.
I recommend starting with Python Selenium 3 Chrome WebDriver .
Do note that Python 3 and Selenium 3 has changed a lot of stuff with automation. So you may have to constantly check with the browser documentation too.
I suggest handling forms and logins in your selenium project. That way you'd learn how to handle captcha and other authentication specific testing too.