how to replicate an effect from davinci

To replicate DaVinci's "Fast Noise" in After Effects, you should use the built-in "Fractal Noise" (or Turbulent Noise) effect. Create a new Solid layer, apply Fractal Noise, and adjust the Contrast, Brightness, and Scale settings until the noise pattern matches the clumpy look of your reference. To get those specific colors and transparency, apply a "Colorama" or "Tint" effect to colorize the noise into blue and white, and then either use the "Extract" effect to key out the black background or simply set the layer's blending mode to "Screen" or "Add." Finally, draw a square mask over the layer to contain it in that specific area!