Open terminal of Raspbain and install libraries (BCM2835, wiringPi, Python) as below

#Installing wiringPi libraries, sudo apt-get install wiringpi
#For Pi 4, you need to update it
cd /tmp
wget https://project-downloads.drogon.net/wiringpi-latest.deb
sudo dpkg -i wiringpi-latest.deb
gpio -v

#Installing python libraries
#python2
sudo apt-get update
sudo apt-get install python-pip
sudo apt-get install python-pil
sudo apt-get install python-numpy
sudo pip install RPi.GPIO
sudo pip install spidev
#python3
sudo apt-get update
sudo apt-get install python3-pip
sudo apt-get install python3-pil
sudo apt-get install python3-numpy
sudo pip3 install RPi.GPIO
sudo pip3 install spidev

Get the script from the github repo

To run the script on startup, run the following command

sudo vim /lib/systemd/system/btc_stats.service

Add this to the file:

[Unit]
Description=BTC Stats
After=multi-user.target

[Service]
ExecStart=/usr/bin/python3 /home/pi/path-to-script/stats.py

[Install]
WantedBy=multi-user.target

Make sure you change the path to the actual path to your script and also make sure that the python 3 file is pointing to the correct location of python3

Now the unit file has been defined we can tell systemd to start it during the boot sequence :

sudo systemctl daemon-reload
sudo systemctl enable btc_stats.service

Reboot the Pi and your custom service should run:

sudo reboot