Nawrot gave you quite a bit to go on. There is no “fighting game” template available at the moment so you will have to build all of the elements yourself. Best bet is to start out with all of Epic’s UE4 tutorials on youtube and learn how to use blueprints.
The camera control stuff shouldn’t be too complicated and the getting 2 characters on the screen is very simple too, the showing both players can be done pretty easily with a trace.