How do I modify fast ai code

Hi, I have installed fast ai using pip on my AWS instance. Now I want to install. I’m on Random Forest video2. I wanted to modify some library code and test things out.

Make sure the newer functions I implement would work. How do I do that?

Also, modify sci-kit functions, add my custom methods to fast ai and when I run them in jupyter they should work.

Is their any guide written on that? If not can someone explain me?