Find the "in" end of your LED strip. For mine, it was the end with the female connector attached - but don't trust that your strand is the same as mine. Check for the tiny green or red dots to figure out the data flow direction.

Leave the "in" end alone for now, and cut off the connector from the "out" end of the strip. For my strip, this is the male connector.

Solder or bolt this connector to your Gemma M0: the red wire goes to VOUT, the middle wire goes to D1 and the remaining wire goes to G. 

If you're new to soldering NeoPixels, check out this guide for step by step instructions.

Plug your light strand in to your Gemma with the connector, and plug in your battery. You should see the first and fourth light come on. Touch the pad on the Gemma marked D0 a few times to make more lights come on.

Trim your strand between the 9th and 10th pixels. Keep the rest of the light strand for another project.