We shall use the PLSQL REST service FND_USER_PKG in this example.
You will have to generate and deploy the service to get the WSDL of the service, which will look like this :
http://adc2180071.us.oracle.com:8001/ISG-ISG-context-root/rest/default/ATGQAFWK_REST_PLSQL_FND_USER_PKG/FND_USER_PKG_REST_Service?wsdl
If you are using SOAPUI behind your organizations firewall, set the proxy settings in SOAPUI. File->Preferences->Proxy Settings.
The steps to follow to get started using the free version of soapUI are as follows :
1. Create a new SOAPUI project using File -> New
Select the check box to add a REST service.
Enter the project name.
Click OK.
2. In the New REST service dialogue box, give the service name and service
endpoint. Select the check box "Extract Resource/Method" and click OK.