Solder the short end of the headers to the LiPo BFF.

Place the QT Py ESP32-S2 onto the headers on the LiPo BFF. Make sure that the pins are matched. The QT Py's USB port should be on the other side of the LiPo BFF's LiPo port. 

Solder the QT Py to the headers.

Your QT Py ESP32-S2 is ready to be battery-powered!