Adding an ESP8266 WiFi module is easy, as the Vinduino board connector J1 is designed for it. The firmware to send your sensor data to ThingSpeak.com can be downloaded from Github.
After downloading, the code needs to be modified, using free Arduino IDE software. Here you can add your local WiFi login information and your ThingSpeak API key. Remove the WiFi module before programming the board.
After editing and uploading your firmware to the Vinduino board, you can use the same programming cable to monitor data being sent to the WiFi module, and the module response data. See picture for the wiring. The gray wire is ground, the white wire is the data. Connect the white wire to J2 connector pin3 for monitoring commands to the ESP8266 module, and pin 4 for WiFi response data. The Arduino IDE software has a serial monitor that works fine for this purpose when set to 115200 baud.
With wire bridge J6 you can set the module power to "always on", or to switching on when an Internet connection is needed, saving battery power.
The communication modules need a battery attached to the battery connector J5. When not using a Vinduino supplied battery, make sure your battery has the correct polarity.