How to change the electronic clock of perpetual calendar into 24-hour timing method

This kind of circuit board is very miscellaneous. There are usually two ways to change the 24-hour clock from 12 hour clock to 1, and press and hold the up button for 5 seconds. This method is difficult to work because the clock is running and it is impossible to directly change the system; 2. Press the setting key to adjust the hours. If the word 12 can't be converted into 13, please hold down the loop until 13 appears, and then you can!