Pygame for Linux also only supports Python 2, not Python 3. If your operating system is Ubuntu, you can install Python by opening a terminal window (from the desktop click on Applications > Accessories > Terminal) and entering "
sudo apt-get install python2.7" then pressing Enter. You will need to enter the root password to install Python, so ask the person who owns the computer to type in this password if you do not know it.
You also need to install the IDLE software. From the terminal, type in "
sudo apt-get install idle". The root password is also needed to install IDLE (ask the owner of your computer to type in this password for you).