Follow the blue quest marker down the hall to reach the stage, dealing with various distractions along the way. When you reach the stage, grab the microphone and Johnny Silverhand will give his goodbye to the crowd. After the performance, head out the door and respond to Kerry however you wish, then get aboard a helicopter.
After another timeskip you’ll fly a bit before you reach the roof of a large building. When your gunner bites it, take control of the turret and clear the roof, then dismount and follow Spider Murphey down some stairs. When she gets the door open, go through it and head downstairs, dusting Arasaka goons with your big iron as you go. Between Johnny’s damage output and his health regen, you don’t really have to worry about much here.
When you reach an elevator, head to the marked location and pick the option to [Plant and arm bomb], shoot the elevator cable when Rogue tells you do, then talk to Rogue. Go through the nearby double doors and shoot your way through the room beyond, following the quest trail upstairs and into another room. Turn left and jack into an Access Point, wait for the virus to upload, then make your way to the marked door.
After another timeskip, head up to the roof and watch some scenes unfold. Say what you want when you get a chance to talk and this quest will end. Playing for Time will begin afterwards.