Welcome to the Ranch
You need to add both halves of the
code tags for your code to look good. I have sorted it out for you this time
Your indentation is inconsistent.
You should use automatic indentation and change tab→4 spaces. I think BlueJ will do that automatically. And that is about the only good thing I have said about BlueJ for years
Write down how you intend to convert the numbers to 12‑hour format. It is quite simple, if you remember the
five arithmetical operators (actually there are about 18 operators you can use for arithmetic) to convert 15 or 3 to 3 and remember there is another operator which will allow you to choose "pm" or "am" easily.
Then all you have to do is work out how to get 12:00am (which is not actually correct; it should be 12:00midnight) from 00:00