When you press the ‘GUIDE’ button to bring up the menu guide you will see ‘All’ in the top left above the channel numbers next to the blue square with antennas.
Each time you click the ‘GUIDE’ button, this filters what channels you see and will change the ‘All’ to either of the following, ‘Subscribed’, ‘SD’, ‘HD’, or ‘Favorite’. To filter through these views, keep pressing ‘GUIDE’ and that will change the filter.