A USB key is one of the fastest and easiest ways to create boot media. You only need a fat32 formatted USB key. Most USB keys come formatted with fat32. It's OK if there are other files on the USB key as long as there is enough room for the image files.
The instructions are for a Windows computer. You can do this on Linux but it's a bit more complex (instructions here)
Download the the zip file with the install image and unzip the files onto your USB key.
Next you need to make the USB key bootable. You need the run a different utility for 32 or 64 bit Windows versions. Replace XX with 32 or 64, in the following commands, depending on your
OS. Browse the USB key and go to /utils/winXX. Right click makebootXX.bat and select run as administrator. Then press enter in the text window.
Your USB key is now bootable.
Put the USB key in the target machine and boot from it. You may need to reconfigure the boot order in your computers BIOS or press F10/F11/F12 (depending on your BIOS) during boot and select the USB key as the boot device.
Once the key is booted select the image to install.
WARNING: Installing an image will erase all data on the target computer
Once your image is installed you will be prompted to reboot power off etc. Select reboot.
Remove the USB key from your machine so it won't boot again.
Your image is installed!