For setting up the wiring and initial code, the image above shows an Adafruit NeoPixel Ring instead of the LED strips. In the code, it's just a matter of setting the number of LEDs.

The Adafruit NeoPixel LED Dots Strands come with black plastic connectors. You can take the end connector, clip it off of the last strand and use it to connect the first strand to the microcontroller. This guide gives a good explanation on how to do this properly. 

You'll also have 2 additional wires coming out of the female connectors, you can clip them for all of the strands, they won't be needed in this project.

Wiring

Start with alligator clips, sewing will come later.

From the NeoPixels to the Gemma, using the pins on the right side of the Gemma, you connect:

• Top strand to GND
• Middle strand to D1
• Red (bottom) strand to the Vout

From the Gemma to the Color Sensor, using mostly the pins on the left side of the Gemma, you connect:

• SCL (A1/D2) to SCL
• SDA (A2/D0) to SDA
• 3Vo to 3V
• GND (on the right side) to GND

In the end, you've should have 2 connections to GND on the Gemma - one from the LED strand(s) and one from the color sensor. And one connection per each of the other Gemma pins.

You also connect the USB connector for uploading the code and later the battery instead of the USB.