I have an idea. I'm going to write up a detailed explanation on how to use this spreadsheet. The beauty of having me, someone without XML knowledge (although NotPron skills come in handy. . . look it up if you don't know what I'm talking about) write about this is that I'm certain to make painful mistakes.
If I write enough misinformation, eventually Kael will have to arrive to correct me. At that point we will have gotten his attention at last and all will be well in the world.
But seriously, I'm going to edit this post with the first of a bit of basic information on how to use this editor.
EDIT:
Alright, time for the first installment of my award winning post series: "How to Use Kael's Editor without Kael (or any knowledge of XML)"
Post #1: Setting up the Editor and tidbits of information on each tab
Kael's editor will give you a chance to bypass the raw XML coding by entering in data you wish to edit into a spreadsheet instead. You simply enter information into a tab that you wish to use, click the export button, and you've got an XML file formatted nicely with all of your information intact.
You will need to put the editor in its proper location for the files to be written to the correct locations, however. Go to the folder you installed Civ4 in, it is probably in Program Files --> Firaxis Games --> Civ4. From there you'll need to enter the BTS folder. From there you'll want to enter the "Mods" folder and then enter the folder of your particular mod (if you don't have one yet, create a folder with the name of a mod you'd like to start.) This is the proper location to keep the editor. From here it will write the files of your mod to their proper locations.
Next you will need to set up the folders the files will be written to. Within your mod folder you will need a folder called "Assets". Within that folder, you'll need a folder called "XML". From there you'll need several folders; it'll depend on what you plan to edit as to how many folders you'll need, but you might as well just create them all. The following are the folders you should create in your XML folder:
1. "Technologies" (No quotes)
2. "Text"
3. "GameInfo"
4. "Terrain"
5. "Events"
6. "Art"
7. "Civilizations"
8. "Units"
9. "Buildings"
Once you've created those, and placed the editor in its proper folder, when you edit something in the editor and then click the "Export" button in the upper left corner (you'll have to click it once per tab you wish to export) the editor will do all the busywork for you and spit out the files in their proper places.
So, once again the location of these folders is likely to be:
C:\Program Files\Firaxis Games\Sid Meier's Civilization 4\Beyond the Sword\Mods\(Your Mod Name*)\Assets\XML\(All of those folders)
*This is where you'll put the editor.
Okay, now for a very brief overview on what each tab at the bottom of the spreadsheet is capable of.
Global Defines: This is where you can set a variety of variables that will affect nearly everything in the game. This tab saves directly to the XML folder, not one of the subfolders you should have created in the XML folder.
Bonus: Here you can create the bonus features on the plots of ground/water. This would be where you create or edit Ivory or Wheat.
Buildings: This will allow you to create your own building(s) with a whole lot of detail. All of the properties of wonders and standard buildings alike seem to be here.
Civics: Here you are allowed to create your own civics.
Civilizations: I don't believe I know how this one works. It seems to be set up for another mod. . .
Diplomacy: This also is set up for another mod and I don't believe it can work for editing. . .
Events: While I am trying to get this to work, I think it is mostly functional. This is where you can create the "random" events that pop up in BTS. This is one half of them anyway; the actual effects of the events are created here.
Event Triggers: This is where you can create the causes for the "random" events. They serve no purpose unless used in conjunction with the Events tab.
Handicap: This allows you to virtually create your own difficulty levels. All of the modifiers for easier settings can be adjusted here as well as those for harder settings.
Improvements: It seems you can create your own worker created improvements. The specifics of building a cottage, for example, would be dealt with here.
Leaders: This appears to be functional for another mod and isn't set up for editing BTS.
Promotions: While there is some modification that is set up for another mod, this is still very usable for editing the level-ups your troops can gain.
Technologies: Stuff regarding how custom technologies function resides here.
Text: Text messages used in the game are neatly contained here and has support for multiple languages. You'll need this for events to function, among other things.
Units: Very very detailed information can be edited here for your own custom units.
Unit Art: I only assume something can be done to make your own custom art for units here but I don't know how it functions at all.
Editor Defines: I'll need some help here, I'm not sure how this tab works.