The document discusses different ways to install various versions of the Ubuntu operating system. Ubuntu 12 and 14 can be installed using an image copy, bootable CD, or bootable USB drive. The installation process using these methods involves extracting the files, running the installer, selecting the installation drive, allocating disk space, and restarting the computer during and after installation. Ubuntu 16 can only be installed using a bootable USB drive, which involves booting from the USB, installing Ubuntu, configuring additional settings, and restarting the system.