Run it, visit the URL, and you're all set to send terminal commands to the host via the webpage. The results will pop up right there on the page.
Please note, any command will be executed, which could be very dangerous for your computer. I can't think of any reason why you'd use it instead of SSH.
If you know what's going on, just go ahead and follow these steps.
git clone https://github.com/winniesi/FlaskCommandRunner.git
python3 -m pip install flask
python3 command.py