A quick overview of WSDL (Web Services Description Language)

WSDL bindings define message protocol and format details for a web service.

Binding to SOAP

<message name="getRequest">
   <part name="term" type="xs:string"/>
</message>

<message name="getResponse">
   <part name="value" type="xs:string"/>
</message>

<portType name="glossaryTerm">
   <operation name="getTerm">
     <input message="getRequest"/>
     <output message="getResponse"/>
   </operation>
</portType>

<binding type="glossaryTerm" name="b1">
    <soap:binding style="document"
    transport="http://schemas.xmlsoap.org/soap/http" />
    <operation>
      <soap:operation soapAction="http://example.com/getTerm"/>
      <input><soap:body use="literal"/></input>
      <output><soap:body use="literal"/></output>
   </operation>
</binding>

The binding element has two attributes - name and type. 

The name attribute defines name of binding and type attribute points to port for binding in this case "glossaryTerm" port. 

The soap:binding element has two attributes – transport and style. 

The style attribute can be "rpc" or "document". The transport attribute defines SOAP protocol to use.

That concludes our quick introduction to things that are important to know. But this is just a start and probably you should be able to check this nice tutorial on Youtube to get some more understanding on WSDL and webservices in general

Here is a nice tutorial available on YouTube by JavaBrains