Instructions
Enter the Episode IV, Chapter 4 level, "Rescuing the Princess." This is the first Death Star level. You need R2-D2 in your party before heading into this level.
Play through the level and follow the linear path through the Control Room. When exiting the Control Room, look out for a blue coin hovering in the distance. Walk toward the coin, but look for a door to the left, near a small gap.
Go through the door and into the hallway. There is an R2-D2 panel on the wall to the left of the door. Have R2 interact with it, then use R2 to float across the gap to a grapple point. Shoot the grappling hook and use it to obtain the red Power Brick.
Exit the stage and go to the Cantina, where you can purchase Extras that you unlock by obtaining Power Bricks. Buy the Tractor Beam power for 15,000 studs.