how to map an IP to a domain name? : I have a website hosted on AWS EC2, it has an IP which is public, I can access the website anywhere from the public IP.

and I have rented a domain name and the provider gave me a console.

I am expecting this console has a field for me to enter public IP. Then it will resolve the connection between the domain name and public IP.

But the console only provide a link called "Modify DNS", and it expects me to provide NS (at least 2). I don't know what to input at all. 

In this case, how can I find 2 NS? or there should be another way to do so? 