In order to make maps for Amnesia you will need to set up the game, so you can easily test maps and reload scripts. First of all, follow these steps to create a dev user:
if(ScriptDebugOn()) { Do your setup stuff }
This will enable you to easily add all kinds of debug stuff (giving lantern, extra items, etc) wihout having to worry about removing it for the final release. Now you should be ready to start some editing!