First, login to the control panel at http://cp.chicagoservers.co
Select your server and navigate to your configuration files:
Edit the configuration to your liking and save it.
Restart your server and your changes will take effect.
The rest of your configurable options can be configured in the Commandline Manager
For more information on that, read this article: https://chicagoservers.co/clients/index.php?rp=/knowledgebase/16/How-can-I-change-my-server-seed.html