You'll need to disconnect the hard drive from the system while you install and configure Windows.  Once it's up and running, you can then reconnect the hard drive.  Note:  currently installed programs on the hard drive will no longer run - they will all need to be reinstalled onto the SSD (even if you decide to install them to the hard drive once again -- all programs need registry entries and other components that are stored on the boot drive).  
Hi. I've searched and researched and am unsure and a little apprehensive about next steps. I Have an Inspiron 15 5570 with 1 1TB HDD and no existing SSD. After checking compatibility I have purchased and received from Dell the M.2 NVMe SSD 256GB. I want to use it for faster Windows 10 Boot and operation, and also use it to run my video and photo editing software. I do not want to clone the entire HDD (won't fit anyways), just get the SSD visible and ultimately become the boot drive for my laptop. I would like to leave the HDD untouched. What is the best sequence of actions to install the SSD, get it ready for use, install Windows 10 files, and change boot order. Again, don't want to impact my HDD. I recently upgraded my memory to 32GB successfully and saw tremendous improvement in reducing disk activity and some speed increase. After reviewing many posts I see lots about cloning, replacing HDD, etc. and some scary posts about problems after upgrades. Any help would be appreciated. Thank you.
Inspiron 15 5570 - Add SSD for Boot but Keep HDD untouched