To use your DGT board on ICC, follow the below steps:
1) Install the DGT software here:
2) Start BlitzIn and navigate to the "Edit" menu option, down to "Settings" and select the "Engine/DGT" tab. At the bottom, check the box "enable DGT board integration". This should bring up the DGT software so that you can make sure everything is working properly.
You should now be able to play using your DGT board on ICC!