How do I stop people going to the next step of the form if they are just filling in blanks?
The best built-in option is to require any/all questions that you need respondents to answer:
This doesn’t force a specific type of answer but it does require that an answer is provided before the respondent can move on to the next survey page.
If you are using open text questions and need respondents to provide a specific type of answer (ex. email), you can validate the question to collect specific kind of data:
Hope this gives you some options!