I’ve always wondered how you can actually start playing Star Citizen, what state the game is in. Here are two recent videos that explain the onboarding for newbies quite well, I recommend watching them both:
The level of immersion is astounding. To recap, right now there is an “Area Commander” mode in the game, where you get to fly ships and dogfight against other players or AI. “Star Marine” is also a playable alpha component, here you get to play the FPS part which is basically just a sandboxed arena shooter with multiple game modes.
Later on there will be a single player story mode called Squadron 42, which is under development, and a persistent game world where everything comes together. Here you get to be whatever want to be and start building up your career, or as Chris Roberts say, “citizenship“.