2 domains, Plusnet webspace. change IPSTAG or use DNS?

[#1]

Hi.
I have my own domain which I brought via plusnet and is in use.  I also have brought another domain els where, and was trying to transfer it in so I can use my PLusnet webspace for both Domain names.  As far as im aware from what iv read I can have upto 5 for free?
During the transfer in, regestering, It  asked for me to change my IPSTAG name with my domain host, but that will cost me £10.  It says on my domain host account that I dont need to change my IPSTAG but use Name Servers instead.
I copied the name server into my Domian host account, what should I do now to have my new domain directed to its own folder on my webspace?
Do I still need to change my IPSTAG in order to use my webspace.   This is all new to me.
Thanks.

[#2]

If you change the IPSTAG to Plusnet then the hosting and registration will be with +net. When it comes the time to re-register the domain it will cost you around £45 via +net.
If you leave the registraton where it is it will more than likely cost you a lot less to re-register.
By just changing the name servers to point to +net you can transfer the domain into +net for "hosting only" at no cost.
+nets help page for this is at https://portal.plus.net/support/domains_and_dns/hosting/domain_hosting.shtml

[#3]

FWIW I think you still have to raise a support ticket after the DNS change, unless the "Domain names" tool on the portal has got a lot smarter since I last moved a domain.