It's teh same process as adding a hard drive, except you should transfer your windows install to the SSD using a tool like this:
http://www.macrium.com/reflectfree.aspx
Or, better yet, you could do a fresh windows install, following these instructions, assuming you are on an Intel platform:
Download the Media Creation Tool from here: https://www.microsoft.com/en-us/software-download/windows10/ and make a bootable USB wiht it.
Get the latest drivers from here:
https://downloadcenter.intel.com/download/25165/Intel-Rapid-Storage-Technology-Intel-RST-RAID-Driver?product=55005
File: f6flpy-x64.zip. Unzip it to a folder on a USB drive(it can be the one with windows on it).
Disconnect all other drives except the one you are installing to.
Go into the BIOS and disable "CSM" and enable "Secure boot" in the Boot section.
Start the install and when it asks where to install hit "have disk" and point it to the folder you put the above files in.
**WARNING: THE FOLLOWING WILL WIPE AND ENTIRE DISK, NOT JUST A PARTITION**
Then hit SHIFT+F10 and:
diskpart
list disk
select disk x(where x is the drive in case)
clean
convert gpt
exit
exit
Hit refresh, select the clean drive, and the "new". Windows will create several partitions and auto-select the correct one to install to(you can also set the size of the partition after hitting "new", but you don't need to if you are using the whole drive).