Create a ninjaform custom field

I need to add a custom field on a ninjaform plugin. This field must be a drag n drop field like other standard field. We will call it History field It should get the content on all previous list field caption, and concatenate it each time the component is set. For example : - The form have the following items in this order : List field1, text field1, hidden field1, list field2, hidden field2, text field2 - Now I put the new component somewhere : List field1, text field1, hidden field1, History field1, list field2, hidden field2, text field2, History field2 The expected result when I will use the [ninja form id="History field1 ID"] is to get List field1 label The expected result when I will use the [ninja form id="History field2 ID"] is to get List field1 label + <br> List field2 label If you don't know ninjaform plugin don't bid on this project. It's a really simple task if you know ninjaform, I will not pay for ninjaform training.