Start off with StarEdit. After you're compotent with it, then go to WorldEdit- the trigger system of StarEdit is very very simple, so it should be easy to pick up- and because they're both Blizzard, the transition isn't too bad. I'll give you a few hints on WorldEdit if they'll help:
+The folder system for triggers is used for your convenience only. You really only NEED one folder.
+Think of events as what you want to actually trigger the action. Conditions are checked after the triggered action happens, if all of the conditional boolean statements for conditions are true, then it executes the action. The action is obvious. Some good ideas for simpifying two triggers that could be one is use the if/then/else command.
+Variables are your friend, don't let them intimidate you.
Explore with these golden nuggets of information. If you then have any more specific problems, I'll be proud to help.