StringTheory has some methods for those things but assuming you don’t have that, just extract the date out of your time stamp convert to Clarion date then subtract date(1,1,1970) and multiply that by the number of seconds in a day
(ie. 24 * 60 * 60).
Then get the time and convert hours and minutes to seconds and add that on.
Usually people use equates for the various conversions as Mark does here: