1. I am not totally sure if your rpm installation/upgrade went well. But it looks like it did.
2. That smb.conf.rpmnew file is a config file for the new upgraded version that you installed. Now, it does that so it won't automatically write over your old one which might have a lot of customized options in it that you don't want to loose like that (I wouldn't) - So basically its just another example smb.conf file.
3. I can't really "create" a config file for you. But I can direct you to a site that offers a step by step explanation on how to write an smb.conf file and set up your Linux and Win32 boxes to access each share. Here it is:
http://samba.netfirms.com - Your completed customized smb.conf file should be put in /etc/samba
4. How do you start samba - I am assuming you are using red hat so the command would be:
$ /etc/rc.d/init.d/smb start
Or to restart:
$ /etc/rc.d/init.d/smb restart
Or to stop:
$ /etc/rc.d/init.d/smb stop
Or to check status:
$ /etc/rc.d/init.d/smb status
You must be logged in as root to execute those commands.
Good luck