What are you doing?
Bought new drive and want to install on it?
Easy way is to only have the ssd attached you want to install onto.
Remove power cable from the other hard drives inside case (unplug pc and make sure it is off before doing this)
so when you get to point in the installer where it chooses drives, it can only see the new drive.
Once win 10 is installed you can reattach the other drive. Make sure the old drive not added to boot order in bios at this point, you don't want to accidentally boot it later on at some stage.
follow this guide:
https://forums.tomshardware.com/faq/how-to-do-a-clean-installation-of-windows-10.3170366/