Hi Kurniapank,If you click the link below and scroll down to Workflow Manager API you can download a package for Silverlight. Inside there will be documentation and code snippets showing examples of method calls. The help doc will be automatically downloaded as part of the Silverlight API download.http://www.esri.com/apps/products/download/index.cfm?fuseaction=download.all#ArcGIS_Workflow_Manager...Cheers,Michael