Open your Sitecore'sweb.config file. Before you start making changes, it is advised that you make a copy of the web.config file, so you always will have the ability to fully recover.
3.1.1 Add handler
DFS has its own handler for serving media files. To enable the handler:
Navigate to the section "/configuration/system.webServer/handlers".
Now add the following handler, inside the handlers section.
DFS synchronizes data from Digizuite™ DAM Center (DC) into Sitecore. Data is stored in a silo (item bucket). Before we can begin synchronizing, we have to fill out some config parameters telling Sitecore which DAM to fetch data from. There are 3 parameters in this file \App_Config\Include\damforsitecore\DFS.Settings.config.
<setting name="DFS.AssetSiloSettings.Default.BaseAddress" value="{URL TO THE DAM SERVER}" />
<setting name="DFS.Digizuite.MediaManagerUrl" value="{URL TO MEDIA MANAGER}" />
<setting name="DFS.Digizuite.ChannelFolderId" value="{ID OF THE CHANNEL FOLDER}" />
We do not recommend that you change these parameters in this file. Instead create a new config file where you patch the parameters (This is best practice). Here is an example of the patch config file. It is important that the file is loaded after DFS.Settings.config, otherwise the patch file won't have any effect. If you name the config file z.DFS.Settings.config and place it in the folder \App_Config\Include\damforsitecore\ you should be safe.