Hi; this project thread pretty well enumerates all the steps I went thru to connect the JJRobotics Devia board to a message -broker shield I designed for the HelTec display. This was all of course for the old Blynk IOT service before the migration to the new 2.0 IOT service. Now that the new 2.0 Blynk code seems to have stabilized and the App is working, I am migrating the code for my original first Blynk project I did for a remote controlled digital salt lamp controller also on this board on a different thread here IR Transceiver using Blynk .
The Fritzing diagram here on " Arduino-based Camera Slider project using Blynk" at about frame 9 on this thread shows a pretty good block diagram of everything; the iPhone Blynk App, the HelTec ESP8266 OLED display running my sketch to talk to the Devia controller, and the stepper motors.