Firstly as with all computer equipment stay calm
For the most robust connections you firstly want to set the IPs for the serve and the western have you done that?
Secondly make sure your western has SAMBA sharing turned on (SMB) they usually come with it turn on but just in case.
NASes are set up with 'shares' these appear as seperate drives on macs and PCs. The shares can offer full guest access or restricted access. How do you have your music share set up? If restricted I would recommened opening it up to be a full accessible share.
Check you can access the Nserve from a browser. You will have by now set an IP for the server so type this into a browser such as Internet Explorer or safari. If the inerface loads then the nServe is ready to rock.
As for the airport, again you need to open this up to SMB sharing. I am assuming perhaps incorrectly you have macs around the house. These use FTP protocol for networking, but can use SMB, in all cases though you need to turn it on. On an airport open the utility then manually set up then there is (or was I have not used one for a while) a tab for the connected printers or harddrives, and somewhere in here is turning on SAMBA sharing. Once done any music on there should be scraped by the serve.
And finally as an experiment use on of your macs to see if its picked up. have some music in a new folder you have created on the mac. Open system prefs and sharing then click on options or advanced and turn on SMB, click ok, back in the sharing pane click on the plus button and add that folder your created with the music in. This should now appear on the serve.
You access all networked info from the system setup>network>manage network shares.
And I believe one last possible complication is the serve might only be showing local music, when browsing music there is a button somewhere to choose 'all music' which will show any networked stuff as well.
Phew, nothing is easy (to start with) on computers.