Route 53 with external Domain Registrar?

I have created a Route 53 hosted zone which contains a SOA, an NS record and a A record.

The A record points to the web instance I have hosted on AWS.

On the registrar what do I need to use to get the domain to use Amazon Route 53, is it just Nameservers? Or do I need an A record or a CNAME?

Which Nameservers should I use the SO or the NS record?

Thanks