#2 Otherwise... At a minimum, I'd watch the Avengers, Avengers Age of Ultron, Thor: Ragnarok, Guardians of the Galaxy, Guardians of the Galaxy 2, Captain America Civil War, Dr. Strange.... I'd consider the other two Captain America's and at least the first Iron Man... and since it just came out Digitally, Black Panther.
Avengers
Guardians of the Galaxy
Ultron (I wanted to leave this out, but Vision / Scarlet Witch)
Dr. Strange
Civil War
Black Panther if you have time, but at the end of Civil War you get all the info you really need to know about Wakanda (it's hidden and technologically advanced).
Those 5 will tell you everything you need to know. The only other thing you really need to know is Thor looses his hammer in Ragnarok and meets Hulk (both of which are in trailers).