1.First Download The intro(well the rar file anyways).

2.Then extract the files into your current mugen's Data folder

3.After that open up system.def and look for "intro.storyboard ="

4.Next to that put whatever the name of the intro Def file is.
(the usual name is intro.def so you would it should look something like this) :
intro.storyboard = intro.def

and that's pretty much it.