Required Software

Some quick points to do/install in order:

You definitely need Arduino IDE
You have to install ESP32 framework for Arduino - follow this guide

at this point you can install ESP32Kiln with OTA Installer, but you will be unable to do some tweaks and you will know ESP32Kiln less - so if it's in your reach, I suggest to go with all next steps.

Install ESP32FS plugin (drop it to "/home/username/Arduino/tools")
Install required additional libraries. Those can be installed from Arduino IDE Library Manager: PID Library called PID by Brett Beauregard, u8g2 and EmonLib if you plan to use power meter. Those, you should "git clone" ESPAsyncWebServer, AsyncTCP, Syslog.
Install also (this has changed in ESP32Kiln v1.1) Saur0o0n's clone of MAX31855 - this implements second HW SPI for ESP32.
Update (there is no other way to do it) in file "libraries/ESPAsyncWebServer/src/WebResponseImpl.h" variable TEMPLATE_PLACEHOLDER to '~'.
Clone/Download ESP32Kiln repository