Based on your system configuration you will currently have a 128 GB m.2 SATAIII SSD so you will want to get a m.2 PCIE nvme SSD like the Samsung 960 EVO or 960 Pro which are currently the fastest SSD on the market.
So based on that you will need to do a clean install since they do not make a PCIE m.2 enclosure only a SATAIII m.2 from what I can find. Download
Windows 10 from Microsoft and put it on a USB stick. Make sure to have SSD drivers unpacked and on the Windows 10 USB stick and may also need to have
Intel Rapid Storage Technology driver also. If your SSD manufacturer doesn't have a driver than you definitely need Intel IRST driver.
During install at the "Where do you want to install Windows?" screen choose Load Driver and load the manufacturers driver for the SSD.
http://i.imgur.com/8vELNb2.jpg
I should also add that you will probably have to change a BIOS setting which you should inquire about at the
ROG Forum.