Ronald’s method of adding IPs will work fine.
However, you said:
1) I heve one default IP address set, but I want to add more IPs to system which I already received from datacenter, I tried "System Settings>Shared IP Addresses", but it's not possible.
You don’t necessarily need to do anything to “add” them to your system–just use them when you need them. So, when you create a new virtual server, just choose to have it on its own IP and fill in the form.
But, if you’d rather the addresses be pre-existing, you can do that to, as Ronald said.
2) when I have this ready, I want to use 2 IPs from these added, and create DNS with my domain name (ns1.DOMAIN.com, ns2.DOMAIN.com)
Ronald is on the right track with his registrar advice, but all of the A records are unnecessary if you’re going o have your own name servers. Running your own is the easiest to manage, since Virtualmin can manage the A records and MX records and everything else for you, once you make the registrar aware of your name server(s).
GoDaddy is extremely irritating when it comes to spinning up a new nameserver from scratch–your name server needs to already exist in some zone that is hosted on some other name server, because GoDaddy doesn’t have a field for filling in the IP address (like many registrars offer).
What this means is that you need to have another name server that is already working and you can add records to, and you need to add your new server it. Then you can give GoDaddy the address you’ve just created for your name servers for your new zone…once that one exists and is resolving you can change the GoDaddy glue records to point to the new ns names.
Confused yet? Yeah, me too. Go yell at GoDaddy for being a wee bit stupid.
Basically, you need an existing name server before you can create name servers for domain names hosted with GoDaddy. GoDaddy’s own free DNS hosting will probably work for this purpose, though, so you can probably spin it all up entirely from within GoDaddy’s interface.
But this is almost entirely outside of the scope of Virtualmin. Once your glue records are right at your registrar, you just need to create two NS records in your domain using the BIND module in Webmin…which I think is pretty easy, and documented in the Webmin wiki:
Adding records is covered here:
http://doxfer.com/Webmin/BINDDNSServer#Adding_and_editing_records
And the types of records are documented here:
http://doxfer.com/Webmin/BINDDNSServer#Record_types