How i create new maps , create custom character and meele attacks

i need to know this to my fighting game , my game will be like tekken and mortal kombat

First take a look at Platformer Game example from Unreal about how you can set up a level, camera, character movement which is restricted to 2d space like a fighting game.

Second, take a look at Couch Knights game example to learn how they do the melee fighting, how to check the hit collision, and animation.

Still a lot of stuff need to do but that’s a base thing if you want to start a fast prototype.