Firstly Install the Arduino IDE from https://www.arduino.cc/en/main/software
Once installed go to Files -> Preferences under “Additional Board Manager URLs” add https://dl.espressif.com/dl/package_esp32_index.json
Then go to Tools -> Board -> Board Manager and search for ESP32. You should have ESP32 by espressif, install this set of boards.
You should then be able to go Tools -> Boards and select “Heltec_Wifi_LoRa_32”
Next to to Tools -> Port and select the apropriate port the dev board is connected to (Windows users will probably need to installed the USB to UART drivers from https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers
Note the board will normally need to be plugged in for the serial port to be present.
Next go to Tools -> Upload Speed to 115200.
Finally got to Sketch -> Manage library and add
ESP8266 and ESP32 Oled Driver for SSD1306 by Daniel Eichorn, Fabrice Weinberg and LoRa by Sandeep Mistry
This should give you an IDE capable of sending compiling the firmware and flashing it onto the dev board
You can obtain Mark’s firmware from https://github.com/unprovable/LoRaChat <Check, the final build may move>
Once you have the .ino file open in the UI, select Sketch -> Upload to send it (it’ll compile it first if needed).
A few seconds later, the firmware should be on the device.
If you’re struggling, there is a more complete guide at https://robotzero.one/heltec-wifi-kit-32/ (just remember to select the LoRa board).