The idea behind flipped classroom is that you assign work for students to complete before the topic is “covered” in class. This student work may involve watching an online lecture (yours or someone else's), completing a reading assignment, or studying something you’ve posted for them. Class time is used in a way in which students apply the information they learned about outside of class. The reason it’s termed flipped classroom is that the content is delivered outside of class time instead of through a typical classroom lecture.
The literature reports that students will do the work outside class, but they must be incentivized in some way. One way to do this is to give a quiz on the content when students arrive to class. Another way is to have students complete a worksheet or short writing assignment about the material. Once the assessment in done, class time is used DOING something to apply the material. For example, students may debate an issue, work in teams to complete a project, work on problems, or design something related to your discipline. The instructor is there to help students as they work through the hands-on activity.
For more information about flipped classroom, watch this 60 second video.