Change to the cloned project directory and open two tabs.
In the first tab change to the folder './backend/go'.
Copy the '.env.example' file to '.env' and change the JWT_SECRET variable to your own secret.
docker-compose build
docker-compose up
In the second tab change to the folder './frontend/react', and start the app with npm:
Register a user, and start playing around in the app to get a feeling for how it works.