The 'Мне нравится' pattern
Use 'Мне (не) нравится + noun' to say you (don't) like something; the person who likes is in the dative case (мне), and the thing liked is in the nominative case.
In Russian, 'I like' is literally 'to me it is pleasing'. The verb 'нравится' agrees with the thing liked, not with the person. For a singular noun, use 'нравится'; for plural nouns, use 'нравятся' (e.g., 'Мне нравятся фильмы'). To say you don't like something, put 'не' before 'нравится': 'Мне не нравится книга'.