Here is the answer: All pins corresponding to the G row are connected to ground. All Pins corresponding to the V row are connected to NodeMCU's 3V3 pin.
D row pins tagged from 0 to 8 correspond to NodeMCU's D1-D8 pins. D row pins tagged with SD2, SD3 corresponds to NodeMCU's SD2, SD3 pin UTART/SPI section:
Tags corresponding to the pins are self explanatory. Near the white-colored power switch we have a pin called "AD". I couldn't figure how this motor shield's "AD" pin is interfaced to NodeMCU. Do you have any idea?
Following on Basic Question - ESP8266 Board Pins, I can't seem to map the pins on its motor shield to software (the ones named UART/SPI, the GPIOs and the Analog Inputs). See the third image, with a NodeMCU installed.
The GPIOs seem to conflict with the motors on Arduino, and I have no idea what to do here. Documentation is pretty much useless.