A method to operate an attachment (1), especially for field shredders, or hay presses, or a self-loading carriages with at least three rotary units is applied. Driving units consist of at least a pickup (3), a transversal transporting unit (2) and a unit (4, 5) for further treatment of harvested mass, arranged behind the latters. The drives of the units (2, 3, 4, 5) form a branching transmission. The branching transmission comprises at least one transfer mechanism (14), dividing a rotational moment. To drive the transversal transporting unit (2), part of the branching power of the transfer mechanism (14) is used. The transfer mechanism (14) comprises at least the first unit (37) to input power and the second unit (38) to input power and at least two units (39, 40) to output power. The first unit (37) to input power is part of transmission with a mechanical unit of coupling and connecting with an output shaft of an internal combustion engine of a carrier vehicle or a pulling vehicle. The second unit (38) to input power comprises a motor (23) of an auxiliary drive. Said motor is adjusted and/or regulated according to the number of revolutions (n). The driving rotational moment (M3) of the first unit (37) to input power and the driving rotational moment (M7) of the second unit (38) to input power are connected with the aid of a planetary gearing (27) according to the superposition principle in such a manner that the number (nQ) of revolutions of the transversal transporting unit (2) is distantly controlled from a cab through the second unit (40) to output power according to the process of regulating, depending on a flow of harvested mass.Заявлений спосіб експлуатації приставки (1), особливо для польових подрібнювачів або сінних пресів, або самонавантажувальних візків щонайменше з трьома привідними пристроями, що обертаються. Привідні пристрої складаються щонайменше з підбирального пристрою (3), поперечного транспортуючого пристрою (2) і розташованого за ними пристрою (