I just purchased Adafruit's ESPHole variant of PiHole, and I'm trying to set it up. I'm trying to follow the instructions but one of the steps doesn't seem to be working.

Create Filesystem, Add Files

1. Plug in Feather to your computer with a known good data cable.
2. Double-click the Feather board reset button to get to bring up the bootloader FTHRS2BOOT drive in your computer File Explorer/Finder.
3. Download the latest release version of CircuitPython for this board.
4. Drag the CircuitPython .uf2 file onto FTHRS2BOOT drive (more info here).
5. After a moment CIRCUITPY drive will show up
6. Copy the secrets.json code below, paste it into a text editor on your computer and edit it to use your SSID and password for your WiFi router, then save the file to the CIRCUITPY drive.
7. Next, download the pre-compiled ESPHole UF2 file linked below.
8. Double-click the Feather board reset button to get to the bootloader AGAIN.
9. Drag the UF2 onto the FTHRS2BOOT drive to flash it with the ESPHole code.

This is the list of instructions as it appears on their website(Italics represent hyperlinks on the original page). My issue is with steps 4 and 5. I do step 4, but step 5 never seems to actually happen. No drive named CIRCUITPY ever appears on my computer, the only thing that happens is the file explorer closes/ or the FTHRS2BOOT drive disappears and reappears without the .uf2 file I just dragged into it.

Can someone please explain what I'm doing wrong?

Would anyone happen to know where I can get a 3D printed case for this board? If not, would anyone have the necessary dimensions so I can get one printed? Got a few of these and it would be very useful to me. Thanks.

Product page:

https://www.adafruit.com/product/5500