It’s an interesting situation. The schematic (.sch) is there, and there is a board (.kicad_pcb) but it is empty, only contains the header. So it looks like the author only used the schematic drawing capabilities of KiCad and didn’t actually generate a board, or if they did, didn’t want to publish it.
So if you want to make a board out if it, you’ll have to learn to do that yourself.
On the other hand, it looks an ATmega 1284A was used, this is a MCU with more memory than the usual 328, see comparision here: https://sepzed.wordpress.com/2014/03/15/arduino-on-1284p-and-1284-non-p-version/ and the Arduino IDE was used to program it. You could avoid building a board by buying an Arduino-like board with the 1284A (https://en.wikipedia.org/wiki/List_of_Arduino_boards_and_compatible_systems), and connecting what appears to be various sensor and relay modules to it with wires.
Then of course there is the firmware, I didn’t look to see if that’s in the repo.