Create a web application with the map service created in the step before.

Create Web Mapping Application
Use a server connection of type ArcGIS Server Local for accessing the map service from within the Web Mapping Application.

Adding a map service of type ArcGIS Server Local
Click through the wizard clicking the Next and Finish buttons.
As a result the created Web Mapping Application should get launched in a new browser window.

Web Mapping Application created with ArcGIS Server Manager
If you are not able to create the service and view it then please check your ArcGIS Server installation, refer to Online Knowledgebase (http://support.esri.com) or contact local Esri support for fixing this problem.