Preparatory Tasks

Here are the first things to do so you can get started creating your client application.

Have a SOAP development environment (one that consumes a WSDL) installed and ready to use.
Contact your Zuora representative to obtain information on accessing the Zuora server, and to obtain access credentials (a login name and password). The Zuora server provides an administrative application that you can use to set certain global properties and to manually perform all the actions that you can perform using the API. When a field in this documentation is said to have its values set in the administrative (Admin) application, this is the application that is meant.
For coding purposes, you will need Zuora's Web Services Description Language (WSDL) file. The WSDL is essential to using the API; it defines the interface to Zuora's Web services. Obtain the WSDL file from within the Zuora web applications - Z-Billing->Admin->Download the Zuora WSDL. This will ensure you have the latest WSDL file.
Import the WSDL file into your development environment. Using the WSDL, your development environment can generate an API to access the Zuora Web services. Your development environment may have a wizard for importing WSDLs; if so, use it.