I am pretty new when it comes to DNS. I got a domain name through GoDaddy.com and I am kind of confused because on GoDaddy's DNS manager, there are entries for MX and NS.

What I am reading is before installing Zimbra, I need to setup a local DNS server.
I need to enter MX and NS there, but that is already there in GoDaddy,

I don't know if I am making sense or not.

Please help me understand.