It depends on the quantity of milk filled in. Usually the preparation takes about 2 to 3 mins.
When preparation has finished, the motor stopped working and the light of the button extinguished.
Please disconnect the plug from the power outlet to clean the power station. Clean the station simply with a soft damp cloth and ordinary washing up liquid.
The power consumption is less than 1 W.
The milk container might not be filled up to the minimal quantity (see indication mark) and the whisk has no or too little contact with the milk. Rinse out the appliance carefully and let it cool down. Afterwards you can start the preparation again.