Videos
1.) Create a folder named "Faction"
...\SEGA\Medieval II Total War\mods\DLV_ext\data\fmv\faction
2.) Then download the video-package, and just drop them in. Now, the video are installed. Alone, the videos do nothing nor harm you.
Directions (aka. descr_faction_movies.xml)
1.) Then it's the directions. This makes DLV know what video to use with what faction. The direction file, is a text ducument. You can either choose the light or the full package, check the spoilers for which to use.
2.) Then open the other spoiler and see where to drop descr_faction_movies.xml, Historical and/or Imperial campaign. Overwrite it, and it's complete.
Either here:
...\SEGA\Medieval II Total War\mods\DLV_ext\data\world\maps\campaign\custom\Historical_Campaign
and/or here:
...\SEGA\Medieval II Total War\mods\DLV_ext\data\world\maps\campaign\imperial_campaign
Just drop it in, and overwrite. Now, you are ready to play, and it is fully save compitable.