From what I read it's a game pack set in Star Wars but it doesn't seem (other than faction names and npcs from series) to require knowledge of SW to enjoy. But simply put
Vi Morada: Black girl with colorful hair and wearing red jacket. She's a rebellion spaceship pilot
Rey: The white gir in a white robe like outfitl playing with a lightsaber and robot. She's a jedi in training
Kylo Ren: The masked dude with lightsaber. He is the leader of bad guys obviously
Ohnaka: The spikey lizard man who talks to the trailer's sim player character in the bar(called Cantina) He is a smuggler
Lightsabers are the rave looking swords ppl use. Droids are the robots running around.
The idea of pack is run around gathering reputation with First Order(bad guys) Resistence (good guys) or Scoundrels (smugglers) or you can just run around and buy knick nacks or never use the world and just use build mode.