On the [Main Menu], select one of the following featurettes: "65 Days of Hell" or "Behind the Scenes".

While viewing the selections, watch for a "DKM" logo to appear in the bottom right of the screen. When you see one, press [Enter] on your remote control. This will pause the feature and play some bonus footage. Once the bonus is finished, the feature will resume. The bonuses all occur at chapter breaks, so they can easily be found by just hitting the skip button.