Best to start by creating and adjusting a character:
Then you can create and set up weapons:
After you create a character with weapons and a few opponents you should add them in your game.
If you're developing a single-player game, use the Game Manager component to add characters and enemies in a scene.
Also, watch the tutorial on creating a single-player game:
If you're developing a multiplayer game, go here:
or watch the tutorial on creating a multiplayer game: