System with drinks preparation machine, a method and computer program for its activation

A method for operation of a drinks preparation machine, for producing a total product from a plurality of part-products, the plurality of part-products comprising a first part-product, a second part-product, and a third part-product, the method comprising:

• detecting a user input for specifying a plurality of quantity shares comprising a first quantity share, a second quantity share, and a third quantity share, wherein a graphic representation of each of the plurality of quantity shares is represented, with a plurality of share displays, each of the share displays being associated with one of the plurality of quantity shares, wherein for each of the plurality of share displays, a size of the respective share display represents the associated quantity share, and the size of at least one of the plurality of share displays and thus of the associated quantity share is adjusted according to the user input;
• producing the total product as a combination of part-products of the plurality of part-products, comprising the first part-product, the second part-product, and the third part-product, wherein a quantity of the first part-product corresponds to the first quantity share, a quantity of the second part-product corresponds to the second quantity share, and a quantity of the third part-product corresponds to the third quantity share;
• wherein the second part-product is milk, and the third part-product is milk froth, and the second quantity share corresponding to a quantity of the milk is limited by a minimum value which is a function of the third quantity share, the third quantity share corresponds to a quantity of the milk froth.