Have you tried to google them?
The first result when I searched Northwind was https://www.microsoft.com/en-us/download/details.aspx?id=23654
It might be different for you since I'm using DuckDuckGo
Luis C.
General Disclaimer:
Are you seriously taking the advice and code from someone from the internet without testing it? Do you at least understand it? Or can it easily kill your server?
How to post data/code on a forum to get the best help: Option 1 / Option 2