The app in question has the purpose of allowing customers who want to train in the Tenet gym to be able to book one or more available lessons. The customer can choose the gym where to train and can choose the coach. Before proceeding with the booking of the lesson, the customer must have purchased a package of lessons, if this has not happened the system directs the customer to purchase a package of their choice. The client can communicate with the coaches and with the management via messages. In the application there is a section for trainers where they can set the availability calendar and a section for the administration that can check the lessons they have taken.