Definitive edition extra videos? can't find them!

So where do i find these extra behind the scenes and stuff videos? because i saw one guy on youtube that it should load up after the splash screens, but nothing… Am I missing something, when i try launch the game off the disc it just takes me to the install menu, I have installed everything other than characters since they just seem to take up space as everything is unlocked and works fine.

edit never mind, turns out i have to launch the seperate file from games menu, thought it might be all rolled into one :confused: