The Adafruit EYESPI BFF for QT Py comes with header pins that you can use to solder this board to the Adafruit QT Py S3, but you need to break them into two segments each 7 pins long.

Before powering up your soldering iron, do a dry fit to ensure you know what you're connecting to where. Make sure that you've connected the two boards the right way around (the flex cable port and the USB C port should be at the same end and each be on the outside of the sandwich. You can confirm that everything's as it should be because the 5V and A0 pins should be against their equivalent number on both boards. The plastic part of the pins should be between the two boards preventing any components from touching.

Keep everything together like this and solder each pin to make the connection permanent. It should look like the image below.

Connect the Screen to the BFF

The EYESPI Cable connects the Adafruit 1.28" 240x240 Round TFT LCD Display to the Adafruit EYESPI BFF for QT Py. On both boards, there is a connector for flat cables. Gently lever up the darker plastic clip gently using your fingernail (or something similar) – it should rotate 90 degrees and expose some contact underneath. On either end of the cable there are exposed metal contacts. The metal contacts on one end of the cable should be placed on top of the metal contacts on the connector, then push the cable as far into the connector as it will go. Once in place, the dark plastic clip can be pressed back down to secure the cable. When it's connected properly, it should withstand a gentle tug – if it comes out, repeat the process being sure to push the cable as far into the connector as possible.

Repeat the process on the LCD side so that cable joins the Adafruit EYESPI BFF and the LCD.

That's the hardware connected, it's time to move onto the software.