Let's give working with windows a shot. Open animal_farm.py (either from a command line by running $ vim animal_farm.py or from Vim with :e animal_farm.py).
Open one of our files in a split window:
You can see that animals/cat.py was opened above the current file and that your cursor was placed there:
You can split the window vertically as well by running the following code:
As you can see, this creates another window in a vertical split (your cursor is now moved to the new window):