Not sure if this will help without knowing more about what you're doing, but storing the date and time in one field is easy enough by using Now function. If you want to show date and time separately on a form, format the bound date field as a date format that you like, and an unbound textbox formatted to show Time as military time. Could be as simple as
=Format(yourDateField,"hh:mm")
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.