In the ESP32_board directory you will find the current firmware (ESP_32_OpenAir.ino) for Version 1.1 of the board
You will need to install the ESP32 Board and the used Libs in your Arduino App.
Instructions for installing the Arduino-ESP32 core for the Arduino IDE can be found here: https://github.com/espressif/arduino-esp32#installation-instructions
The dependencies can be picked directly from Manage Libraries in the IDE.
Selecting ESP32 Dev board in Board Manager should work fine.