The community is also a great place to check out. Try this link for help from other users:
Please review the Third-Party Game Support topic to determine whether your question should be directed to the game developer or to Steam Support. Sending a support request to the wrong party may result in a delay in processing your request.
If you're encountering issues when launching or playing Napoleon: Total War, make sure everything installed correctly.
Exit Steam entirely.
Browse to your Napoleon: Total War installation folder (Usually C:\Program Files\Steam\steamapps\common\napoleon total war\)
Run the following installers:
Reboot your computer and test the issue again.
To view the additional content for this game that is registered to your account, please do the following:
All additional content listed in this window has already been downloaded and integrated with your game. If you are having trouble accessing or locating the content, contact Napoleon: Total War support for detailed instructions.