Destroy everything in the park across from the Dispantser and then master build the three parts to create a truck. Once built, the Red Brick will appear.
Collect the three instructions located in the lower train station, the balcony beside the blue and pink fence, and where you use the drill near the entrance to the construction site, then use the construction station to reveal this Red Brick.
Use the platform in front of the police station once Unikitty breaks it and reassembles it. Fly over to the building where the shack is, and then hop to the left of the crane there. Use a wrench on it to toss a podium over to the park. Go to where it lands and then push it in front of the fountain and the Red Brick will appear.
To get this Red Brick, you will need to return 5 cats to cat lady who is located beside the Dispantser. The cats can be found on the upper level of the train station where you need Benny to hack the terminal, in the outhouse atop the building with the crane, in the lower train station where you will need to hit the large switch to the right with the tall Lord Business.
To make Lord Business big, you can build his platform by destroying the red dumpster beside the construction yard entrance. The fourth cat is on a balcony to the left of the cat lady, where you will need to break the bench below and rebuild to make a grapple spot. **Note: this cat automatically returned to the lady by itself for some reason** Pull the balcony down to free the cat. The final cat is to the right of the balcony where the instruction piece is sitting in the same area. Break the blue and pink fence and then bounce up to the right and shimmy across the ledge to the fenced area.
Collect Guide Studs
Master build the three billboards in the area to change them into “Question Authority” signs and the Red Brick will appear on the grass near the train station.