https://help.hover.com/hc/en-us/articles/217282457-How-to-Edit-DNS-records-A-CNAME-MX-TXT-and-SRV-Updated-Aug-2015-
https://help.hover.com/hc/en-us/articles/217282457-How-to-Edit-DNS-records-A-CNAME-MX-TXT-and-SRV-Updated-Aug-2015-
https://help.hover.com/hc/en-us/articles/217282457-How-to-Edit-DNS-records-A-AAAA-CNAME-MX-TXT-SRV-
A or AAAA records are for IP and IP6 respectively.
CNAME records are for when you're offering a web application on www.gnucode.me & gnucode.me. It's a way of using the A record to define the IP address, and the CNAME just turns www.gnucode.me to the A record IP address.
https://support.dnsimple.com/articles/cname-record/