Open your Sitecore'sweb.config file. Before you start making changes, it is advised that you make a copy of theweb.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.AssetSiloSettings.Default.Username" value="{USERNAME FOR THE USER TO BE USED WHEN SYNCHRONIZING BETWEEN SITECORE AND DAM}" />
<setting name="DFS.AssetSiloSettings.Default.Password" value="{PASSWORD FOR THE USER TO BE USED WHEN SYNCHRONIZING BETWEEN SITECORE AND DAM}" />
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 said 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.