PRESTASHOP - create cascading dropdown category

Sirs,

I am trying and banging my head to create a cascading filter for Prestashop, based on its categories, and the plugins I found are paid for. What would be the best way to do it?

If only Prestashop returned me a json, I would get popular dropdowns with the categories, but I ended up running out of the north ...

This is my structure:

<div id="filtro">
                        <form>
                            <div class="form-group">
                                <label class="col-sm-12 control-label">Montadora</label>
                                <div class="col-sm-12">
                                    <select style="width:100%" name="montadora_tur" required="required" class="form-control" id="montadora_tur">
                                        <option class="montadora_zero" value="">Selecione</option>
                                    </select>
                                </div>
                            </div>

                            <div class="form-group">
                                <label class="col-sm-12 control-label">Carro</label>
                                <div class="col-sm-12">
                                    <select style="width:100%" name="carro_tur" required="required" class="form-control" id="carro_tur">
                                        <option class="carro_zero" value="">Selecione</option>
                                    </select>
                                </div>
                            </div>

                            <div class="form-group">
                                <label class="col-sm-12 control-label">Ano</label>
                                <div class="col-sm-12">
                                    <select style="width:100%" name="ano_tur" required="required" class="form-control" id="ano_tur">
                                        <option value="ano_zero">Selecione</option>
                                    </select>
                                </div>
                            </div>
                        </form>
                    </div>

Would anyone have any light?