The process is:
1. Select a Preset (if the Preset has Programs already loaded, skip step 2).
2. Select Programs to place in the Shell Preset.
3. Go to Control tab, click "Allow Generator Overwrites", and then select generator to run it on.
4. Once selected, the Start or Scan button should be click-able.
I know the Start button is not click-able if there are no frequencies to run, so a Program isn't loaded in a Shell. Not sure if there are any other reasons.
If you load programs under Programs tab, you need to double click it
For more details, please check the link: