I'm not entirely sure, but you seem to be asking 2 questions:
1. How to install Windows 10
2. Can you an SSD as the only drive.
Is this correct?
1. Purchase Windows 10. It will arrive as either a DVD or USB. Or a ISO download
You use this to install the OS. You don't install it 'from the BIOS'.
2. Yes, an SSD as the only drive is OK, if it is large enough.