Over-caffeinated Nephil

I'm very sorry if this is a really stupid question, but I just downloaded the BoA scenario editor (for Windows) and can't figure out how to install it. The Scenario Workshop page says to look at the README file once I have the editor, but I can't find that, either. I just got an icon that says "BoAEditor", and when I click on it, a window pops up asking me what program I want to use to open it. There is nothing resembling a README file that I can find. Can anyone tell me where to access this README file, or better yet give me instructions on how to install the thing? (Also, does Blades of Avernum need to be registered before the Editor will do anything, for that matter? I know I need the registered version to play other scenarios, but do I need it to create them?)