In OCTGN, open the GAMES MANAGER tab and in the drop down menu on top-left select "Community Games".
Install Duel Masters OCG from the games list.
Click 'Add Image Packs' in GAMES MANAGER and install the image pack file you downloaded.
You can now go to Deck Editor to build your deck. Start a game from the 'Play or Spectate' tab. To translate jap cards in deck editor, press F12. To set up translator(proxy) inside duels, go to OCTGN options -> Zoom behavior on cards -> Display proxy when holding CTRL