While there are plenty of resources out there, I'm going to tell you how I did it and had success.
I gave myself a project. At that time, it was a website crawler, Amazon to be more specific.
As I had no idea where to start, I started using StackOverflow for questions regarding functions.
An example would be "StackOverflow python selenium visit page"
As your code is being put slowly together, you will need to use a huge variety of functions, a lot of the basic ones like string search, concatenation, etc.
By the time you finish your project, you will have a decent amount of basic knowledge in python.
I'm not saying it's a good way of learning. But it's how I did it ( 6 years ago ) and has worked great for me.