@Cindy13 The most reliable way to set the 30-second skip is while watching a normal TV channel.
Press "Exit Exit Exit" (wait 1 second between button presses; do not press-and-hold Exit) and then key in "0 0 3 0", also waiting 1 second between button presses.
Yes, you should see 0030 search results on the right side of your screen. Press Exit to cancel. After that, 30-second skip should be enabled when watching Live TV and recorded content. The skip interval may be different when watching some On Demand content.