GoDaddy URL . Naked domain works, WWW. does not. HELP!?

[NewClassicAdmin]

I have set up the A Name to the IP specified. Naked domain works wonderfully, but www.domain does not. 
What am I doing / not doing? 
CName is only set to store.squareup.com if I am forwarding only a subdomain, correct? 
Or by store.squareup.com do they mean 'my stores' unique @squareup address?

Guess I'ma keep trying, your assistance is appreciated!!

[Helen]

It sounds like you've followed the steps to configure your subdomain correctly @NewClassicAdmin: You should point your CNAME record to store.squareup.com, and the host for that should be www or store. Or are you seeing an error message after you follow the steps? Also keep in mind it can take up to 72 hours for the changes you've made to appear.

If you're still having trouble can you reply with a screenshot of your GoDaddy's configuration settings? (Feel free to send as a private message if you'd prefer.) With that we can take a closer look.