1. Download the Arduino IDE.
2. Install and run the Arduino IDE.
3. Click Tools, Manage Libraries..., and search for MLX90614 and install Adafruit MLX90614 Library (not the MiniMLX90614!).
4. Click Tools, hover over Board: (...) and click Boards Manager (at the top). Search for Arduino AVR Boards and install it.
5. Click Tools, hover over Board: (...) and click (in the list) Adafruit Circuit Playground.
6. Connect the system to your computer with a micro-usb connector (not the USB-C connector, that can only charge the battery).
7. Click Tools, hover over Port and click the port that says Adafruit Circuit Playground next to COM.
8. Download the code in this repository by clicking here.
9. Unzip the .zip file into any folder (other than your Downloads folder).
10. Open the main folder, and open the main.ino file. (The Arduino IDE should now open).
11. Click Upload (the green, right-pointing arrow at the left top) to upload the program.

The parts you can easily modify are the top 20-odd lines (excluding the first and second line). They are configurable settings for the system.

You can also modify the rest of the code, but you must make sure you know what you're doing as to not compromise stability.

Enjoy!