ASSEMBLY

• Break any remaining tabs off of the circuit board. Sand the broken edges smooth if you're a perfectionist (like me).
• Lay the ESP-12F face down on the circuit board, align the traces, and solder it down. Use flux if you have it.
• Strip the ends and solder the insulated wire from the EN pin on the ESP module to the pad right below the gear symbol on the circuit board.
• Trim the resistor lead lengths to 20-25mm.
• Lay a Pi Zero on the foam, component side up.
• Stab resistors through the Zero all the way into the foam, in GPIO holes 13, 15, 16, 18, 22, 35, and 37.
• Tease the free ends of the resistors into the proper holes in the circuit board and push the board all the way down until it sits on top of the resistors.
• Use hot glue or whatever to prop up the ESP end of the board and hold it in place while soldering.
• Stab the solid wire pieces into the remaining three holes and into the foam, until they only protrude a bit above the circuit board.
• Solder the resistors and wires to the circuit board and trim the ends.
• Pull the assembly out of the foam, solder the resistors and wires to the Pi, and trim the ends.
• Remove the glue or whatever you used. If you used hot glue, the bond can be easily broken by applying Isopropyl Alcohol.
• Clean up any flux residue.

QUICK SOFTWARE SETUP

• Download the 2016-5-27 Raspbian image and copy it to a fresh SD card.
• Download from the files section esp8089.ko, config.txt, and esp8089.dtbo, and copy them to the SD card's FAT32 partition.
• Boot the imaged SD card in the Pi and do the usual initial configuration.
• Reboot and log in.
• Move /boot/esp8089.dtbo to /boot/overlays.
• Move /boot/esp8089.ko to /lib/modules/4.4.11+.
• Run the command sudo depmod.
• Reboot and the WiFi adapter should work! Of course you need to configure which access point to use, and a password if needed.

HARDER SOFTWARE SETUP (FOR EXPERTS)

• Compile the kernel module for the kernel you're running. The source is in the esp8089.tgz file.
• Copy the compiled kernel module to the proper modules directory and run depmod.
• Copy the esp8089.dtbo file to /boot/overlays.
• Add dtoverlay=esp8089,poll_once=off to the /boot/config.txt file.
• Reboot.