I have MSI Laptop (MSI GE60-20E). It has a Windows 8 Single Language. I bought an SSD and installed it. I wanted to re install the Windows 8 Single Language to the SSD. ( I have downloaded a copy of Windows 8 Single Language) Can anyone give me instruction on how to do it? i backup all of my important files to an external drive so everything left to the laptop is good to go.

Starting from Windows 8, new machines have the product keys embedded in BIOS and at the time you re-install Windows it should automatically detect the product key embedded.
When you say "fresh install", do you mean to say clean install?
As you have downloaded a copy of Windows 8 Single Language, you can boot the computer with installation media you have created and continue with the installation.
Important: Kindly back up the data before performing the installation. Fresh install (clean installation) will erase everything (even apps that you may have installed) from the computer and only Windows will be installed.