I'm not much further along than you, especially in sabayon, but here goes.
"Search" is located below the 'a' in the sabayon title on top of the forum page.
In 'SabayonLinux General Discussions', the top thread called 'Resources and Forum usage' is your friend.
To install a package, as root in the command line, type 'emerge --search packagename', ie 'emerge --search amarok'. This will tell you if the package is installed, and if not what is the proper name for the package. To install, 'emerge packagename.' This can take a long time depending on the package - that is the nature of sabayon/gentoo. Don't worry if it seems like nothing is hapenning for awhile.
You mentioned nero in your post. K3b is included in sabayon and is a much better cd/dvd burning package than nero for linux. Give it a try.