1. Distributions. To install Linux, you will want to choose a distribution.
   1. Ubuntu. Seems most popular right now.
   2. Fedora. My favorite.
   3. Mint. A relatively new one that has some popularity.
   4. Debian. An old standard, which is actually the basis for some of the shinier ones.
2. Some roads less traveled.
   1. Slackware. Probably the oldest surviving distro. Also probably the hardest on this list to install. Don't try this one unless you want an extra learning experience.
   2. Archlinux. This distro is intended to be particularly lightweight for use on a small (possibly old) system.
   3. Gentoo. You probably don't want to try this one until you've accumulated a bit of Linux experience. Definitely don't pick it first. Gentoo is is a source-based distribution which installs packages by downloading the source, compiling it, and installing the result. It is very flexible (so you need to know what you're doing to pick options), and can produce a fast installation by leaving out what you don't want, and customizing to your system.
3. There is also Knoppix, which is mainly intended to run without installation, but also has an install option.
4. Linux can be installed on Mac hardware, but I have never done it, and can't give you any better advice than “try Google.”
5. Installation Media.
   1. The install process involves creating some removable media and booting from that instead of the computer's hard drive.
      1. Long ago, we booted from a floppy drive.
      2. More recently, CD-ROM, the DVD-ROM.
      3. Most common now is to use a USB thumb drive.
         1. Get a thumb drive which contains nothing you need to keep. At least 2G is generally sufficient.
         2. Visit the distribution download site and download the install image. This will generally have an extension .iso.
         3. Copy the image to the thumb drive. Red Hat's instructions, as Ubuntu's for Linux, Windows, and Mac should work for other distros as well.
   2. Once you create the install media, you need to boot it on the target platform.
      1. Insert the thumb drive and reboot.
      2. If you're lucky, the computer will boot from the thumb drive into a Linux install environment.
      3. More likely, you will need to get your computer to either
         1. Enter a BIOS boot menu so you can choose to boot from the thumb drive rather than the hard drive.
         2. Enter the BIOS setup so you can change the boot order to check for a boot-able thumb drive before checking the hard drive.
         3. Getting to the BIOS involves striking a key during boot. Best to Google the procedure for your machine model.
      4. When the install media boots, you will be running a specialized Linux, with a (usually large and obvious) icon to begin installation.
6. Disks and partitions.
   1. Linux will be installed to some hard drive, which need not need to be the main hard drive.
   2. If you want to run multiple OS's using a single hard drive, the drive must be divided using multiple partitions.
   3. The installation process will set up partitions as needed.
   4. Partitioning may involve destroying the existing OS or other data. Linux installers are pretty good at asking, in large letters, if that is what you want before proceeding.
   5. Partitioning need not destroy the existing software. See the next section.
7. Where shall I put Linux?
   1. An old PC you were planning to throw out is an excellent option.
      1. Linux is more efficient than Windows, and the latest releases can run fine on hardware built for Windows XP.
      2. This is a very easy install. Just tell the installer to replace all existing data on the hard drive, and it'll just go.
   2. It is possible to install Linux along with some existing OS and choose which to run at boot time.
   3. A dual boot configuration requires separate disks, or separate partitions on one disk. There's a hard way and and easy way.
      1. Share an existing Windows install.
         1. The disk will not have room to create a Linux partition.
         2. Most installers will have an option to shrink the Windows partition.
         3. There is risk of corrupting Windows, but I've never seen one fail.
      2. Install on a flash drive.
         1. Before starting the install, plug in (another) flash drive which doesn't have data you want to keep. 16G is sufficient.
         2. Select this new flash drive as the install destination.
         3. Works better with USB-3. Check the plug and the device; if they don't say they're 3, they're not.
   4. Install Linux on a virtual machine.
      1. Enable or install a virtual machine manager such as Hyper-V, Virtual Box, VMWare or Parallels (which I don't think you can get free).
      2. Create a virtual machine.
      3. Boot the virtual machine using the install media as a virtual DVD ROM. No need to create boot media; just use the downloaded image.
      4. Likewise, the virtual machine will have a virtual hard drive, and no partitioning of a real drive is needed.
   5. Knoppix
      1. Download and create bootable media.
      2. Intended for use that way.
      3. There is also an install-to-flash option.
         1. Allows you to store files that survive reboot like any normal install.
         2. Very portable.
   6. I'll be happy to give you an account on Sandbox. You can access that from Windows using Putty, or SSH on Mac.
8. Since the Mac Terminal app runs Bash, you can run many of the commands in the course there. But probably not everything.