Start by downloading Debian. The file I used for this guide was debian-7.3.0-amd64-netinst.iso, 7.4.0 seems to be the current version. If you have a USB CD drive you can burn the ISO to a cd and boot your rig from that. The other option is to write the ISO to a spare flash drive with Rufus. I've used both methods and they work equally well.
You will need to insert the flash drive you intend to install Linux on and the drive you are booting from (CD or flash) and power up the system. Most motherboards will automatically boot from whatever valid boot media it finds, if not you will have to enter the BIOS and set your boot device. Make certain to connect the network cable because files need to be downloaded during installation.
Select language, country and key map.
Enter a name for your rig and leave Domain name blank.
Enter a root password and verify.
Enter the name and username for a user account. I use "riguser" for both.
Enter the user password and verify, then select your timezone.
Here, sda is the flash drive I am installing Debian from and sdb is the flash drive I want to install it to. sdb already has a partition so I select it, hit enter and choose delete on the next screen.
sdb now consists entirely of free space, so I select it again and hit enter. Choose "Create a new parition" and use the maximum size.
Choose to create a "Primary" partition. In Partition Settings highlight "Mount options" and hit enter, then select "noatime" with the space bar and hit enter again.
Highlight "Bootable flag" and hit enter to turn it on. Then choose "Done..." and "Finish..."
Choose "No" on the swap partition warning, it's not needed. Choose "Yes" to write changes.
Select your country to get a list of mirrors, choose a mirror and enter a proxy if needed (probably not).
Choose "No" for popularity-contest, use the space bar to select "SSH Server" and unselect everything else and install GRUB.
Remove the drive you used to install from (CD or flash) and continue. Your system will reboot to your new installation of Debian. If the login promt comes up ok disconnect the monitor and keyboard and login with use SSH from another computer.
