title: How to make a "workflow" form
body: <p>For my project I need many "workflow" forms. I explain myself:</p>
  
  <p>The user selects a value in the first field, validates the form and new fields appear depending on the first field value. Then, depending on the others fields, new fields can appear...</p>
  
  <p>How can I implement that in a generic way ?</p>