Data Connection

The Circuit Playground must be connected to the "in" end of the LED strip.  Data flows one way through the strip, from "in" to "out".

• Circuit Playground G --> Neopixel G
• Circuit Playground A1 --> Neopixel IN

Power Connections

The power supply will be connected directly to the strip, so power doesn't need to all flow through the Circuit Playground.  Drawing too much current through a microcontroller can be problematic, so it's good practice to run the power directly to the NeoPixels if you have a long strip. 

Connect the + and - wires from the screw terminal to both the NeoPixel strip + and -, and to the Circuit Playground's battery port.

Powering

Choose an appropriate power supply to support the number of LEDs you have.  A small 2A power supply will work fine for up to around 60-80 pixels.  If you have 150-200 like me, you may have better success with a 5A or larger power supply.  Just remember that whatever supply you use, you must give the project 3.7-5V.  Any larger voltage will fry your pixels, or a lower voltage won't be adequate to run them.

Head over to the Neopixel Uberguide to learn more about power requirements.  For up to around 200 LEDs I found the 5v 4A power supply to be totally sufficient.