If you want to ask follow-up questions based on previous answers you can do this by setting conditions to your button's action.
Let's say you have the following scenario. You have a start question that let's the visitor rate the satisfaction of the website. If the visitor give a low satisfaction rate you want to ask a follow-up question. If the visitor give a high satisfaction rate you just want to submit the form.
You can do that by setting a condition in your action of the button. Click the button -> Add an action (if not already added) -> Add a condition -> set your condition -> set the response. In the example above we will redirect all answers from 1 to 5 to go to the next page (where we will have the follow up question). Save your changes and go back to the button settings.
You will need to add another Action that handles answers 6 to 10. So add a new Action.
Add the condition and then set the appropriate response(s). In this example we Submit the form and close the popup if the visitor is satisfied with the website (rated 6 or above). But you could as easily route them to another page that has a follow-up question for your satisfied visitors.
Notice! The available condition is based of the input type. As the conditions are checked in order of added action it is really important to add these in the correct order to prevent strange/faulty behaviour. Remember to check all routes in Preview before activating your Popup/Survey.