for out some data from form you must add it to DataOutputSet.
If you use jbpm5.4 click on
https://community.jboss.org/servlet/JiveServlet/downloadImage/2-810574-20685/294-215/for+answer.png
there is HTML-editor with some templates for make easy form.
use Ctrl-Z for add defined variables.
For input variable something like this: <label> ${some_input_var}</label>
For output variables <input type="text" name="some_output_var">
