This "Try it Out" says "you need to add the name Start to DNS".. Add it as a CNAME or as a DNS address? And mapped to what name\IP address?

HI,
It will be a Host A record to IP address (ip of the interace listening on the sharepoint server).
As the book states. The entry in the sharepoint sections will only work when it is implemented in the DNS. So for http://start (internal dns need to have a host entry called start with ip address of the sharepoint server). External dns entry for your traffic to come through to the sharepoint server to process.
I hope above clarifies some issues.

Regards,
Nasir