Once your server object extension (SOE) or service object interceptor (SOI) is deployed, you can enable it on a service. Do the following to enable the extension:
Find your service in ArcGIS Server Manager.
Begin editing your service by browsing to the service and click its name, which is a hyperlink.
Click Capabilities and check the box next to your extension name. SOEs will be listed under the general list of capabilities while SOIs will be listed in a separate section for Interceptors.
If enabling an SOE and if applicable, select the operations you want to allow for the SOE. These operations were optionally created by the SOE developer, and they give you a finer degree of control over what users can do with the SOE.
If applicable, set further properties on this page as exposed by the extension developer. Some extensions do not expose any properties at all.
Save your changes and dismiss the dialog. The service is restarted when you save.