Using the SPI Flash SD Card breakout with CircuitPython is as simple as wiring it up to a microcontroller and using the Adafruit CircuitPython SD library.
It is not recommended to use this with Raspberry Pi and other single-board computers as you already have a full filesystem available to you.
Wire up your SPI Flash SD Card breakout as shown below. This example shows a Feather M4 wired up using SPI.
Check out the CircuitPython page in the CircuitPython Hardware: SD Cards guide for everything you need to know about using your SPI Flash SD Card breakout!