Head into the building as marked - and talk to the receptionist. She'll tell you that the plans are up on the top floor and you can now go to the stairs as marked on your map.

You can see that the plans are on a wall at the end of the hall. But now you have to make a distraction downstairs in order to take the picture of them. Once you do, then run all the way out to the street and hop in a car. You're up to four stars now. Run back to the casino to deliver the film.

mission passed!
respect +

Grand Theft Auto San Andreas Walkthrough