Flashing with esptool - download the executable from Espressif's Arduino-ESP32 repo https://github.com/espressif/esptool/releases (download esptool-vx.x.x-win64.zip, place esptool.exe in the same directory as the files downloaded here), connect the board to the PC, flash it by running ProgramESP32. You will be asked to provide the serial port corresponding to your board.