How to add minutes, seconds, hours or days to a datetime value

Simply add the desired interval to your timestamp value:

select current_timestamp,
       current_timestamp + interval '3' minute "current_timestamp+3min" 
from dual;


CURRENT_TIMESTAMP                                 current_timestamp+3min
----------------------------------------          ---------------------------------------------------------------------------
24.08.2016 19.44.32,808781 +2:00                  24.08.2016 19.47.32,808781000 +2:00

There are numerous possibilities to add very granular time intervals to an existing datetime value.

Check the examples of Interval literals in the official documentation.