Confusion setting up server

Linux and Unix-Like Linux
1

20GB space (1GB Swap),and installed Centos 5.7-x86 arch. I want to use this VPS to host 2-4 domains, all of WordPress. What I want to ask is:

  1. Do I need a VPS management software before installing Webuzo (from Softaculous)? If yes, what was his name?
  2. Do I need to install the software before installing the VPS Management or already included in the VPS Management? For example, I have to install MySQL, PHPMyAdmin, and all that is required by WordPress.

Thanks.