Alpha Fade on Character change

Hello;

I am working my way through an early Oculus demo with several actors and would like to add a simple Alpha fade when “switching” between characters. This is my blueprint for the change of characters:

How can I add an alpha fade to this blueprint? (I have searched and seen mention of timeline but am unsure what to add to the timeline to give a full scene alpha fade).

Thanks for any help;

Anyone able to give me a few hints on this at all?