I implemented only two-axis control (X and Y), because that’s all I need for my photography.
The project thread pretty well documents all the steps from inception to delivery, with lots of pictures and videos. I interfaced to two camera sliders - the JJRobo and a longer Neewer.
The Arduino code sketch I wrote uploads into the HelTec OLED Display board that has a full ESP8266 WiFi stack to communicate to the Blynk server. The Devia board does not connect to Blynk. I used the HelTec rather than a Nano or a Wemos D1 board because I wanted a cool blue built-in display on a Nano-sized board to talk to the Devia. I designed a very simple Arduino-sized PCB board sourced from JLCPCB to hold it and some interface resistors that bolts right into the side of the JJRobo slider, or sits in an acrylic project case when using the Neewer slider, as you can see in the pictures. The Devia board thinks it is getting commands from the JJRobo custom App, but in realty they come from the Blynk iPhone App.
Caution: be extremely careful handling the stepper-motor connector wires where they push onto the Devia PCB board pins. The pins are surface-mount and easily dislodged from the PCB substrate. I have gone thru damaging 3 of their boards and ultimately ended up having to solder the connector wires directly to their board. I hear they are stabilizing the pins with epoxy glue until they sell thru the current production run of Devia boards. I hope they then switch to plated-thru pin connections to eliminate the initial design problem.