On this repository you can to find examples for python library RPI-ST7789.
First of all we need to connect ST7789 to raspberry pi as on this picture:
Next install python3 for work with RPI-ST7789 library:
sudo apt install python3 idle3
To work with examples without camera.py you need to install the RPI-ST7789 library:
pip3 install RPI-ST7789
And for the work camera.py you need to install another library opencv-python and connect webcam to raspberry pi.
pip3 install opencv-python