First of all: If you don't feel absolutely confident with Linux donn't install Gentoo. See that's a convicend Gentoo advocate who's telling it.
Normally you shouldn't have *any* problem with a soundblaster card. SB are 100% supported. Perhaps your problem is trying ot configure it, when the card was indeed already configured.
First thing to check, before trying to reconfigure a soundcard is checking if the card has been unmuted: Kmix or Gnome-alsa-mixer will do the work. Check also if there is an icon representing a speaker in you panel / task bar: If the sondcard don't work the speaker appears crossed wit a red bar.
Second thing to ckeck if you are using KDE / Gnome is if the sound has been activated in the desktop: K Menu > Control Center > Sound and configure the settings. In Gnome look in Gnome's own control center.
One thing to keep in mind when you post asking for help is telling us which distro you are using, specially in regard to soundcards as every distro has it's own setup tool.
Before jumping to Gentoo I would give SUSE a try, as it's (IMHO) the distro which includes better hardware recognition and autoconfiguration and also the distro which can offer a better experience to the new user including a shallower learning curve and a faster ooverview of the many features of modern Linux systems.
Ah, and if you finally decide to give Gentoo a try, take it easy, Gentoo is not specially userfriendly to install, but there is help available and lot's of documentation... And there is also a nicer way to install a Gentoo system using Mayix [http://www.mayix.net
], a more userfriendly Gentoo based distribution.