Okay, in the general settings, in the time format section, check the ‘Custom‘ box. At the moment there is probably just ‘g:i a‘.
g: Hour, 12-hour, without leading zeros
i: Minutes, with leading zeros
a: am, pm
So for example, if you wanted to set it as, 10:58 pm, you would just write ‘10:58 pm‘.
Hope this is what you want.