I'd probably suggest to start off by reading the docs and manuals at http://httpd.apache.org
And for the servername, well, if you have your own domain name, you'd want to place that there. But remember, setting up your own domain on your own server, you need a DNS server too so it knows where to find it when it translates from name to IP, etc.
You can use free DNS services like www.zoneedit.com
if you don't want to set your own up, etc.