Understand the difference between the twenty four hour clock and am and pm!
Please get your heads around the difference between the twenty four hour clock and am and pm!
03.00 pm, which is what the system comes up with is completely ambiguous - it's either 15.00 or 3 pm - with the 24 hour clock you don't need am or pm, that's the whole point of it!
You can change you date and time format, including 12 or 24 options, in Settings / Organization page. See https://help.wildapricot.com/display/DOC/Organization+details for details