Properties of an end product, such as paper, paperboard or board, are important for the user of the end product. To be able to manufacture an end product of desired quality, it is important to know what kind of paper pulp used for manufacturing the end product results in a particular kind of property of the end product. Embodiments provide a method and an apparatus for generating a model, which model connects at least one property of the end product with at least one property of the paper pulp. On the basis of the model, also the manufacturing process can be controlled.