The link to your document is broken, but it sounds like you're trying to set up the Linux system as a router between the Windows VM and the outside world.
According to your explanation, you haven't set a default gateway on the Windows machine. Therefore, it does not know that to get to the Internet it's supposed to go through the Linux machine. You can confirm this by trying to ping 8.8.8.8 from the Windows VM; if you get a reply, your gateway is set up properly. If you don't get a reply, try setting the default gateway on the Windows machine to 10.0.0.4 and trying again.