You may install Virtualmin on a fresh system as the following instructions:
Step 1: Run the command "yum install perl" for installing Perl;
Step 2: Run the command "wget http://software.virtualmin.com/gpl/scripts/install.sh" for downloading Virtualmin GPL;
Step 3: Run the command "sh install.sh" for installing Virtualmin;
Step 4: Open a browser and visit the url "https://YOUR_IP_ADDRESS:10000" for the management of Virtualmin.