Connect PowerBoost to Pi
We'll need to power the Pi and Speaker Bonnet with the PowerBoost. Make two more pieces of wire, about 14cm in length. Using wire strippers, remove a bit of insulation from the tips and tin them with a bit of solder. Pieces of heat shrink tubing can keep these two together.
Connect Wires to PowerBoost
Solder the wires to the 5V and GND labeled pins on the Adafruit PowerBoost.
Connect PowerBoost to Speaker Bonnet
In order to power the Pi with the PowerBoost, we'll need to connect the 5V and GND wires to the pins on the Adafruit Speaker Bonnet. 5V and GND pins are conveniently broken out on top of the Speaker Bonnet. Solder in the two wires from the PowerBoost into any available 5V and GND pins.