Use a wizard to add a web reference for a C Sharp integration.

Go to the Solutions Explorer and select Service References > Add Service Reference. A wizard will appear. At the bottom of the form, there is an Advanced button. Click on it and click on the Add Web Reference button at the bottom of the new wizard page. This will start the Web Reference wizard. For the URL, use: https://<instance name>.service-now.com/incident.do?WSDL and name the web reference, 'WebReference1'. Accept the defaults for the rest of the wizard.