missing example usage

[ohdavid2018]

This is a very useful program and will help my project a lot. The installation instruction for Raspian Jessei works for Buster also. However can someone provide a few examples for how to use the program? A short wiki will be even better, if you guys are busy, then please threw in some examples or links, I can create a wiki for rest of us. I got issue like 'error:cannot open framebuffer device - No such file or directory' when try to run it. Many thanks!