How can I install docker tool and build and publish my image? I did but I have this error?
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
It means the Docker daemon is not properly installed or not in a running state.
You can check the condition by sudo systemctl status docker, if you fund it to be stopped or not active.
Try restarting it with sudo systemctl restart docker.
If the problem persists, You need to debug your Docker installation, and probably re-install it referring to this doc for your OS/Arch.