Because you want the pistons to be by default and extended only when the plate is stepped on, you must use a Redstone Torch to invert the signal. Place a Redstone Torch behind the pistons.
To build a standard version of this trap, you will need the following items: 4–8 (depending on the scale). Redstone Dust: 10–15 pieces. Redstone Torches: 2 (for signal inversion). lovely craft piston trap wiki full
Cover the Redstone wiring with grass or stone blocks to match the surrounding environment. Use "bait" like a Chest or an Iron Door at the end of the hallway to entice the target to walk over the Pressure Plate. Because you want the pistons to be by
Stone is recommended (as they cannot be triggered by dropped items). Building Blocks: Solid blocks like Stone or Obsidian. Step-by-Step Construction Guide 1. The Foundation Redstone Dust: 10–15 pieces