Installation:
1. Locate your Assassin's Creed Valhalla folder 
-Usually its C:/Ubisoft/Ubisoft Game Launcher/games/Assassin's Creed Valhalla/videos/
-Or you can find this by clicking the game in Ubisoft connect, then go to properties and local files
2. make a back up of the folder assassinations 
Paste the "assassinations" folder into the "Videos" folder

3. Replace the 6 files when prompted
4. Launch the game and enjoy!

Unistallation:
Or make a back up from the assassinations folder
Delete all the files included in this download from your "Assassin's Creed Valhalla" folder and verify files in Ubisoft Connect

Disclaimer:
I am in no way responsible for your game breaking! This should not be happening anyway since this only replaces the startup videos with less than a second long videos. Use at your own risk.