The paper defines the models of the objective tree and the current reality tree. Such models allow to define problems on the basis of cause-effect relations. The paper provides general recommendations for the application of these models. It describes their application on the example of an information system, a compound program complex. The information is accompanied by visual images in the form of diagrams. The information system is used in the field of retail to solve many different problems. The paper explains the need to identify problems. Within the framework of the example, the system's stakeholders are defined and their interaction with the objective tree is given. After that, a certain objective is considered and the reason for that is given. As a result of using the current reality tree, the paper compiles a list of root problems. At the end, it proves the connection between the solution of low-level problems and the implementation of high-level objectives. Finally, it provides recommendations for further work related to the selected list of problems.