Following on ESP8266 Board pins, how do they map on the motor shield? 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.
You see the pins marked PWMA, PWMB, DA and DB? Those are the pins that control the motors (PWMx is the speed, Dx is the direction). Whatever pins on your ESP8266 board plug into those holes are the pins you need to use in your code. How those pins map to names and numbers in the Arduino API depends entirely on what the board is you're plugging in and what the author of the board definition files was thinking at the time. 

In short, look at your board (which we cannot see) and see what GPIO pins are in the same location as the pins I pointed out. Then control those pins in your software.