When assembled properly the HD Stacker antenna has a VHF/UHF single output. The CM 7778HD has two switchable input choices. It has the option of VHF/UHF combined input or separate VHF and UHF inputs. The unit comes preset to combined input meaning the single input labeled "combined" will amplify both VHF and UHF signals. Connect the antenna to the combined input of the CM 7778HD and both VHF and UHF signals will be amplified. The CM 7778HD also has a switchable gain control. In your case supplying multiple TV locations set the gain switch to the high position. Remove the 4 screws on the bottom cover of the preamplifier. You will see 3 switches. One switch will have the option of (L) for low gain and (H) for high gain. Set it to (H). Leave the other two switches as they are set from the factory.
Switch #1. Combined or Separate input. Set to combined the preamplifier input labeled combined will amplify both VHF and UHF signals. Set to separate the preamplifier input labeled VHF will amplify VHF and the input labeled UHF will amplify UHF signals.
Switch #2. FM trap. Factory preset to the (IN) position. If the antenna in use will be used for FM reception set the switch to the (OUT) position.
Switch #3. This is the (High) or (LOW) gain switch.. In weaker signal areas when supplying multiple TV locations set this switch to the (H) position.