Endpoint www. domain added fine but how to add non www to redirect to https://www

Question

I am quite new to Azure and I have made a static web page with literally just an index.html in the storage. I have setup the endpoint with a custom domain of www. and added the CNAME which works perfectly if I go to that domain url but if I do it without www. it directs to the 123 reg parked page. Any one able to help with how to sort this out? I have tired adding the domain to the custom domain tab without the www. but I get the error of cannot find the dns record CNAME for the domain but it seems I cannot add a CNAME record without a hostname.