Complex sentence: Before the second winter period, the Moomins and their friends also get to know Alicia and her grandmother witch, who teaches Alicia to become the real witch but is not impressed by the Moomins and their nice nature.
Split into simpler sentences: Before the second winter period, the Moomins and their friends also get to know Alicia and her grandmother, who is a witch. She teaches Alicia to become a real witch and has a negative opinion about the Moomins and their nice nature.