when you install an OS there will be some additional small partitions related to the install. these can vary depending on how the OS is installed and who installed it. SOme OEMs will have recovery partitions and the OS will also have some system reserved partitions in some cases. This partition is not related to the sandisk ssd.
An SSD come from the factory as unpartitioned RAW storage. You must use disk management or some other partitions software to create a partition and format the SSD. If you have Windows install disk this is done prior to beginning the OS install.
It may be best if you research a little more on on installing an operating system so you are a little more familiar with the process.
