Adding one or multiple fields to structure

Hi
I’ve set a structure with three fields just like this :

  related:
    label: Texts
    type: structure
    style: table
    fields: 
      title:
         label:       Title
         type:        text
      langue:
         label:       Language
         type:        text
      pdf:
         label:       Fichier
         type:        quickselect
         options:     files
         placeholder: Choisir un fichier

The user wants now to be able to add one or multiple pdf and langue for the same title. What is the best way ? Do it programmaticaly ? Is there a plugin (v2) to add fields inside a structure ?

I’m a bit confuse on how to do it.

I was going to write use a nested structure, when I realized you are on Kirby 2, not 3.

There was this plugin for Kirby 2: https://github.com/kirby-deprecated-plugins/field-engineer

No idea if it still works.