This means that users can get through the program only after answering the series of questions given.
Explanation:
The statement<em> "users advanced through the program by answering a series of questions"</em> means that users can pass to the next level of "the program" by providing the correct answers to a series of questions. This means that to move to the next level, providing correct answers is a requirement.
So, when users can provide answers to 'the series of questions' provided, they can move on to the next level of the program. Advancement through the program requires the users to provide answers to the "series of questions" in the program. In short, unless one answers the questions, one cannot advance or move on through the program.
