Minecraft Server In Need With Help Groupmanager

Hello I Am A Owner Of A Awsome Brand New Server And I Need A Little Help With My Groupmanager Plugin I Have Loads Of Other Plugins Like Factions But I Need Help With This One http://legendzx.webs.com/ That Is My Website Of My Server And I Have My Server IP Here 71.107.141.51 Please Tell Me How To Add Prefixes And The Default Rank Now But See You On My Server Or Contact me at Packofthebeast@gmail.com