Grand Theft Auto: San Andreas Walkthrough

Woozy and CJ begin planning their epic heist. But first: they need the architectural plans. Time for CJ to step up.

Before you head to the plans, you need to obtain a camera. Head toward a group of tourists on the street, marked by a red blip on your radar.
As you approach them, pick the tourist taking the photo and kill him. Steal his camera.
Now, head to the city planning department, marked by a yellow blip on your radar.
Once you reach the spot, head inside. Be careful not to show any guns, as they are prohibited inside and will sound the alarm.
The plans are on the top floor. Turn around and to your right to go inside the stairwell.
Go up the stairs to the top floor. Once you reach the top, you'll be prompted to create a distraction so that you'll be able to photograph the maps in private.
Head back down a floor and down the end of the hallway. In the room at the end of the hall is a air conditioning unit, marked by a yellow blip. Destroy it to set off the fire alarm.
Once the alarm sounds, head back to the top floor and down the hallway to the Caligula plans. Take a photo.
Once you take the photo, the cops will be tipped off to you. Time to make your exit. Head back down the stairwell to the first floor.
Be careful as you make your way down, as police officers will fire at you and meet you every step of the way.
At the bottom level, head to the front door, marked by a yellow blip on your radar.
Once outside, make your escape back to the hotel, marked by a yellow blip on your radar. You'll attract a 4-star wanted level, so tread carefully.
Reach the hotel in one piece and you've completed the mission.