There are two methods for installing LiteSpeed's WHM Plugin: from within WHM itself, or from the command line.
Navigate to the WHM Plugins area and search for LiteSpeed Web Server Plugin for WHM. You can install the plugin from there.
From SSH as root, run the following commands:
cd /usr/src wget http://www.litespeedtech.com/packages/cpanel/lsws_whm_plugin_install.sh sh ./lsws_whm_plugin_install.sh rm lsws_whm_plugin_install.sh