How can I find Ste? I remember that in the previous version they let me go to the farm through the cave, but I don´t know what to do
Have you already freed him from Vicoria's prison?
If so, go to the Forest Path, and look around until you find the cave entrance. That cave entrance leads to the path to the farm.
Eventually, after you get him to like you enough you can get him and his kids to visit Bareshade, and then he'll speak with Bernard about clearing the overland path to the farm.