Besides the survey I’ve executed with Gizmo, I’d like to add additional responses data from a previous survey I made using a different service. How do I combine all the data in one report?
It sounds like the Data Import tool might get you what you need. This tool allows you to import data into your survey. The data will need to be in a specific spreadsheet format. The below SurveyGizmo documentation should be a good place to start:
Hope this helps!