1. to install windows, you need windows installation media.
If you want to install windows 10, then create windows 10 installation media first.https://www.microsoft.com/en-us/software-download/windows10
2. Set sata controller mode to ahci before installing windows.
3. disconnect hdd, connect ssd, boot from windows installation media and install windows (the same windows 10 version you have currently (home or pro) or else windows will not activate). When asked for install key, skip the step.