Bellsouth model 1188 digital ans machine

Press and hold the "clock" button. You will hear a beep and the display will begin flashing a number which represents the day of the week. 1=sun, 2=mon, and so on. Press the left and right arrow buttons to scroll through. After choosing the day, press the "clock" button again to set the hour. It will start with 12 am and go through 11pm. Press "clock" again after setting the hour to set the minute.You will be able to scroll through 0-59 to choose the minute. When finished, press the "clock" button again to exit the time setting feature.