welcome to dungeon craft!
once you've got the editor up and running, either select level--event editor or the 'E' button. click on the square you want to place the monster's in. an 'event viewer' box will open up. on the right side top, there is a drop down menu for 'event type'. if you want the monster to fight your party, look for 'combat', or if you want to talk, 'text statement'. if you want options, try 'encounter'. after choosing this, you can decide what triggers the event as well. after deciding what type of event, look on the lower left of the box for the 'add' button. click here and decide the specifics of the event in the new box. click 'ok' when you're done. the box disappears and then click 'close' in the event viewer. voila! you have added monsters!
don't forget to save before you exit...
hope this helps.