I would say, start with the first item. Install Python 3.
LINUX
If you are running linux, you probably have Python v2 and Python v3 already installed, to test, type "python3" (w/o quotes) in a terminal window You should get information about Python, followed by 3 ">". Type "exit()" (w/o quotes) to return to the command prompt.
As for "pip", it may or may not be installed. To check, from a command terminal type"pip3 -V", if it's installed, you'll get the current version number (should be 9.0.0.1 at this time), if not you'll get an error.
If you need to install "pip", from a command terminal, type "python3 -m ensurepip". This will install pip, but you will need to upgrade it, so type "pip install --upgrade pip"
WINDOWS
If you are running Windows, download the correct version for your OS (i.e. 32 or 64 bit) from Python's website:
Download Python. Navigate to the location you downloaded the file to and double-click to install. I would recommend you create a directory named "C:\Python35" and install it to that location. For all intents and purposes, you can accept all the "default" options, make sure you check the option to install the environmental variables and pip. To test the installation, open a terminal window and type "python", you should see something similar to:
C:\>python
Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:18:55) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
As was mentioned, if you are just starting Python, the tutorial you have selected is most likely to advanced for you at this point and you should look for a beginners tutorial.
Have fun