This page of the Spider-Man Miles Morales guide describes the Curtain Call quest. Here you will find a way to get rid of the barrier on the theater roof and the location of all the generators needed to turn on the Nuform silo.
Location: Upper East Side
Rewards: 5000 XP
Getting rid of the barrier
Follow the marker to the theater in the Upper East Side. You will find an entrance protected by an electric barrier on the roof of the building. Scan the environment to find the three generators you need to turn off. You will find two generators on nearby roofs, and one on the square in front of the building.
Each of them will be guarded by a group of Underground members. Take them down quietly or in an open fight. When the power is cut off, return to the roof of the theater and use the Venom Smash to get inside.
Use the L1 R1 on the sprocket and then quickly fire your web (R1) in its direction a few times to lift the elevator shaft and get to the next room. Go to the silo and use the computer. Miles will have to turn the power on to check what's inside.
To do so, switch on four nearby generators. You will find hints about Phin's activity in the Underground around each generator.
Switching on the generators
Go to the balcony. Use the Venom Punch(L1 square) to smash the wall with graffiti on it and then the Venom Smash to smash the floor. Turn on the generator.
Press R3 and find the mechanism controlling the backdrop. Just like with the gear, first use L1 R1 to start the mechanism and then shoot the web quickly several times (R2) to raise the backdrop. Go down and turn on the generator.
Unfortunately, it is not connected to the cables directly. Hold L2 and aim at the relay and then connect it to the generator. Scan the environment and connect the next two generators. Go back to the computer and watch the next cutscene.
After the fight, Miles will start chasing Phin. During the chase, watch out for her bullets and dodge when your head turns red. At some point you will start running up the building. From time to time Phin will fire traps in your direction. Dodge or jump over them. After reaching the roof of the skyscraper, watch the last cutscene and finish the mission.