If you want to create an agency or a commission recipient, go to persons > commission recipient/agencies and create a new contact.
Fill out the fields accordingly.
However, as customer type, select "Agency". Make sure that capacity and authorisation are set to the correct setting and enter a username and a password here as well.
Under provisioning the corresponding rates are to be entered.
As a user of the module "Credit" you can enter for each agent an amount under "Credit Account", that defines the maximum amount for his bookings. You can log payments here anytime.