*Read about M.2 SSD at the end as you may prefer that instead...
You'll use one of the FOUR, dark brown SATA connectors.
However, you also have SATA EXPRESS (otherwise you'd likely have SIX normal SATA connectors). You can find out more if you want in the following video, however chances are you'd never use it: https://www.youtube.com/watch?v=GQEvOr55Pf8
You also have an M.2 SSD connector in the middle which would be an ideal thing to use for your Windows drive. The price is comparable and it uses no connectors and stays out of the way.
*Read about M.2 SSD at the end as you may prefer that instead...
You'll use one of the FOUR, dark brown SATA connectors.
However, you also have SATA EXPRESS (otherwise you'd likely have SIX normal SATA connectors). You can find out more if you want in the following video, however chances are you'd never use it: https://www.youtube.com/watch?v=GQEvOr55Pf8
You also have an M.2 SSD connector in the middle which would be an ideal thing to use for your Windows drive. The price is comparable and it uses no connectors and stays out of the way.
The only disadvantage I can think of is if your M.2 SSD connector failed or if you wanted to use the SSD elsewhere later with another computer but then it's not really too expensive and will be worse even less later on.
*Either way, make sure to download the Samsung Magician software which is used to update the SSD firmware, test, apply profiles etc.