All resellers and accounts management is done via WHM in cPanel. You should be able to access it by https://your.server.ip.address:2087
(replace your.server.ip.address with appropriate IP address) with root login details. Tutorials on using the most popular features of WHM are available under Dedicated Hosting Tutorials section on http://www.lunarpages.com/tutorials/
. Please be advised that it is not possible to have more then 1 user with cPanel access to the account.
Please update this topic, if you have more questions or concerns.