The AddDateTime() adds a period (h hours - default - or m minutes) to a date and returns it as a result.

AddDateTime('Date', 'quantity', 'identifier')

AddDateTime('2014-12-15 01:00:00', '10' )

return 2014-12-15 11:00:00

AddDateTime('2014-12-15 01:00:00', '10', 'h' )

return 2014-12-15 11:00:00

AddDateTime('2014-12-15 01:00:00', '10', 'm' )

return 2014-12-15 01:10:00

AddDateTime(ActualDateTime("yyyy-MM-ddTHH:mm:ss"), '120', 'h' )

Now plus 120 hours