Hey @Marcosdm1771996,
sorry for the late reply. Did you already find the solution?
Generally I can sugest you our guide section, we have a couple of guides for the halloween event: Halloween quest (Complete, 2019), Halloween quest (2020), Halloween quest (Gengarite, 2021).
If you are still stuck, please let me know what you did last and I will try to help you out what to do next.
Kind regards~