I haven't watched those vids in some time, but I believe they are up to date enough. Some minor details have changed (for example, the WorldSide object is now a Faction object), but the principles are all sound. If you have any questions, feel free to ask.
If you are trying to do anything complex, note that pretty much all the minor factions are implemented entirely in external code (aka stuff that's accessible to modding), so I would strongly recommend looking at them for examples of how to do things. In every case there's an xml component and a C# component.
If you watch the videos and also check out some of the existing minor faction code then you should be in a good place to start.