I really like these little modules, they can be had very cheaply from aliexpress. They have a CdS cell, an RGB LED, a micro usb port for power (and linear regulator that can run the module) and a button on them. They come with a little programming board with a CH340 usb-serial converter, and reset/flash buttons. The reset button wiring is pretty obvious. The button on the esp board goes to GPIO4. The ‘flash’ button goes to GPIO0. The RGB LED goes to pins 15, 12, 13 active high. The little blue led on the module is tied to GPIO2 which is why it blinks when programming. The CdS cell is tied to the analog pin, it spits out between 50 and 1024 (basically the whole range). They program exactly like a nodemcu 1.0
The rest of this series can be gotten through from the home page here.