Activating the Help Center and Selecting Display Mode 
The adaptation of the Help Center to the technical features of ABAP application types (transaction dynpros and Web Dynpros) results in the following differences:
Help Center for ABAP transaction dynpro applications
The Help Center is deactivated in the default setting. If you have activated it, it opens in a browser window when the application help is launched.
Help Center for Web Dynpro ABAP applications
The Help Center is activated in the default setting using a application parameter. It opens in a browser window when you call the application help. You have the option of displaying the Help Center in the side panel of the Web Dynpro application.
Procedure
Activating the Help Center for ABAP Transaction Dynpros
In the SAP system, open the Project Implementation Guide for the Help Center.
Choose
SAP NetWeaver 
Knowledge Management Help Center 
.Choose
(Activate Help Center).Set the Help Center Activated indicator.
Optional: Selecting Display Mode for the Help Center for Web Dynpro ABAP Applications
If you want the Help Center to be displayed in the side panel of the Web Dynpro application, change the value of the display parameter.
More information: Application Parameters and URL Parameters (Web Dynpro ABAP)
Note
Whether the Help Center is displayed in the side panel or not depends on the space available in the Web Dynpro window. If there is not enough space to accommodate the minimum Help Center width requirements, the default setting applies and the Help Center is displayed in a browser window.