Windows can't see it as a secondary drive because it has no partition on it. Click on start and in the search box type Disk Management and click on the top result. From there you will be able to right click on the drive and format as NTFS. These drives are better suited as the main drive for an OS vs as secondary storage so cloning to this drive with software such as Macrium Reflect is best.
I personally use MiniTool Partition Wizard free edition for easy cloning of OS partition. Which is all you should honestly be doing with an SSD. Using an SSD for data is like bringing in Wolfgang Puck to make you Kraft Mac N Cheese.