1. A method of establishing rules for a device used for generating decision support for decisions which determine the behavior of an entity and/or for controlling the behavior of an entity, which device comprises: a supervising unit arranged to handle a rule system for the behavior, wherein the supervising unit comprises at least one storage member in which a rule structure comprising a set of completely or partly ready-formulated rules for the behavior is stored, a user interface comprising first means for presenting information to a user of the device and second means for inputting instructions to said supervising unit, wherein the device is arranged such that said rule structure is such that a rule comprises one or more premises and one or more conclusions, wherein the device is arranged such that the rule system is divided into a plurality of states for different parts of said behavior, wherein each state comprises one or more of said rules, wherein the device is arranged to via said first means present a decision support window which comprises at least one area which represents one of said states, wherein this area comprises names which identify different rules which form part of the state, wherein said method comprises the steps of: running said device in a real or simulated version of said entity such that the entity goes through a behavior or a behavior scenario, said decision support window to a user, allowing the user to make decisions by, via said second means, inputting instructions which mean that one or more conclusions which form part of a certain rule, the name of which is currently shown in said area in the decision support window, shall be executed, analyzing the decisions which have been made by the user, and determining or modifying the rules for which the user has made decisions concerning that one or more conclusions shall be executed out in accordance with the analysis that has been carried out.