how do I add multiple questions to a poll?
By definition (at least in SurveyGizmo) a poll is a single question survey. Polls also have additional limitations. See: https://help.surveygizmo.com/help/polls
If you want to ask multiple questions, you will need to create a Survey instead of a poll. Assuming you want to show results to the respondents like a poll, you may also want to look into the Results Chart action. See: https://help.surveygizmo.com/help/results-chart