Solder three wires to the NeoPixel strip as follows:

• NeoPixel - to Feather G
• NeoPixel DIN to Feather 13
• NeoPixel + to Feather BAT

We're soldering to the BAT pin because this is a 3v logic board, but the NeoPixels prefer a bit more voltage than that. This pin will take voltage directly from the battery without level-shifting -- meaning your pixels will be a bit brighter.