Perhaps your book is not the same as the one I'm looking at. Let me give you a link to the electronic (PDF) version of the book that I have for the 2747 module. That book should appear when you click the link below.
Once you have that, look at the section titled "To toggle between 12-hour and 24-hour timekeeping" (page 1 right column), for the steps to switch between those two modes - and try to set it to 24-hour mode.
THEN, once in 24-hour mode, use the "Digital Time and Date" and "To set the digital time and date" sections, to set the appropriate time.
NOTE - if it is between 1PM and midnight, the digital time should now be displayed in values between 13:00 and 23:59 (that's 24-hour mode).
Please give these steps a try and let me know the results. And let me know if you have any trouble viewing that book, or finding the sections I mentioned.
If this has answered your question(s), please take a moment to rate MY service level (5-star is my goal) so that I get credit for my time helping you with this question.
You should see some "stars" to do that, but please let me know if you do NOT see them (you may have to scroll UP or DOWN) or can not use them.
Thanks, ***** *****