OK it's actually simple and hopefully it will work (no guarantees). Make sure you have a free USB port and you have a Windows 10 image (iso) installed onto a USB stick. 
 
1. Install the M.2 with adapter in your PC
2. Disconnect any other hard drives and/or optical drives
3. Load up Windows and see if the drive is recognized
4. If it is recognized simply make a new drive and load windows
5. If the drive isn't recognized check the BIOs and see if it is seen there. 

For Windows 10 you might need a driver as well. 

I've had install problems before and used Diskpart to set up the drive..Install media should have an option to run Command Prompt..Or, since you already have Win7 installed, you can use Diskpart from an Administrator Command Prompt (or even Disk Management) from within Win7 to set up a partition for Win10, which might be more easy.
 
You can try Diskpart to set it up instead of letting Windows try doing it on it's own and see how it works out.
 
Delete the existing partition..Create a new partition..Clean/Format to NTFS and Convert to Basic Disk and MBR if it isn't already, mark as Active.
 
Something like that..I forget exactly what I did, it's been a while ago, but maybe all this will help or at least point you in the right direction.
 
More on using Diskpart and getting information on Drives/Partitions here and here and other places you can search for.
 
And it might help to know exactly what drive you have if you continue to have problems.
 
Good luck with it.