Login to the SSH with the root password.
Change to directory >> CGI
cd /usr/local/cpanel/whostmgr/docroot/cgi
wget -N http://www.netenberg.com/files/free/fantastico_whm_admin.tgz
tar -xzpf fantastico_whm_admin.tgz
rm -rf fantastico_whm_admin.tgz
Login to WHM, and follow the link WHM -> Add-Ons -> Fantastico De Luxe WHM Admin.