CWP operates with 3 types of users.
root - is the default admin. It has the highest level of access and can manage all aspects of the system (install/uninstall system software, change system settings, et, create resellers/regular users). root has access to each account on the server. However, there is no option to add/remove domains to root account for security reason.
reseller - this type of users can create/remove extra user accounts, has access to the accounts created by the reseller. It can't manage system settings, install/uninstall server side software or change system settings.
regular users - regular users have lowest level of access. They can manage their own account only (add/remove email accounts, domains, etc).
So you need to create at least one user level account to manage the websites. If all websites belong to you then you are free to create just one account and manage all websites through one account. However, it is better to create separate user level account for each website. If the websites are managed by different users then create extra account for each user.