Skip "Sign in to your Microsoft account" (Windows 8.1 Setup) [duplicate]
Click Create Account
On the next page, ignore all the textboxes to enter your names and details etc - at the bottom is a small link that says "Continue using my existing account."
This will allow you to keep using the existing local account
It's very sneaky of Microsoft to hide this option away. Most people who want to keep their local account will not be able to find this
You can also go to you account settings and click on 'Disconnect'. This switches your online account to a local account without any data lost!