Unpacking ETW .pack files
To be able to modify Empire: Total War, you first have to unpack the game's files. Here's how to do this.
Backup
Go to your Steam\steamapps\common\empire total war demo folder. Inside this folder you’ll see four other folders and several files. Right-click on the folder called data and click copy, then right click on an empty spot in the demo folder and click paste. Windows will now copy the data folder and it’s contents. Do this so you have a backup copy of your files just in case something goes wrong with the unpacking or modding.
Unpack the zip
Download the unpacker here. Extract the files from the zip using Windows’ build-in zipping utility or a separate program like Zipgenius. Place the emp_unpacker.py (the Python script) and the unpack.bat file into the following folder: C:\Program Files\Steam\steamapps\common\empire total war demo\data. (If you’ve installed Steam somewhere different you should use that folder.)
Install Python
To use the unpacker you first have to install Python. The Python installer can be found in the unpacker download. Extract and double-click the Python-3.0.1.msi file and install it on your computer. You don’t have to put Python inside your ETW folder.
Unpack the files
Now go back to the ETW\data folder and run the unpack.bat file. All files from the .pack files will now be extracted into a temporary folder called unpacked. Copy the contents of this folder and then paste them into the main ETW\data folder.
Rename the pack files
You must now remove the extension from the demo1.pack file. For example change it's name to demo1_backup. If you don't do this your modified game will not work. (If you cannot see the file extensions, in the toolbar at the top of the screen go to Extra » Folderoptions and remove the check in front of hide extensions for known filetypes.)
