See the documentation here: https://docs.mendix.com/refguide/parse-and-format-date-function-calls
So for instance formatDateTimeUTC([%CurrentDateTime%], ‘ HH') would give you the hours, formatDateTimeUTC([%CurrentDateTime%], ‘ mm') the minutes and it depends on how you want your days but you could use something like formatDateTimeUTC([%CurrentDateTime%], ‘ dd').
You can now do all kinds of stuff to add or change these values and to parse them to dates again.
Hope I did not misinterpred your question.
Regards,
Ronald