Screen navigation based on userregistration form using webapp


Can you help me on How to validate for multiple fields using expression in camunda?


Is it possible to add a custom variable to the response along with the existing json response data when the rest api is called in camunda.


How to go back to step2 from step3 in camunda so that it will be with the current step in UI?
For example as as said above with screenflow, the user selects next so that goes to next step but i need to modify the previous screen again but camunda task points to the current instaed it also should go back and point to the previous step