If you are able to read german, check out the excellent Oracle APEX community website hosted by Carsten Czarski of Oracle Germany. There are a bunch of How-To articles, which walk you through complicated stuff by providing a very detailed description what to do. Piece of cake, as the Americans would say!

Every two weeks two new topics are covered. Last edition covers Exporting via commandline and About DBMS_SCHEDULER.

This site is a must read for german Oracle APEX developers!