I'd be tempted to delete all patitions and start from scratch.
Windows 10 will create
- a system reserve partition approx 350Mb (contains boot configuration files)
- a C: drive where windows is installed
- a recovery drive containing the recovery menu and tools
1 and 3 will be hidden showing no drive letters but 3. will show as x: drive when the recovery menu is accessed.
When you have sorted it to your own needs I suggest you download and use Macrium Reflect Free to make an image of the drive to an external source and the recovery media. That way you can restore windows in just a few minutes.