How to download and setup os
Open terminal and run command
                                            git clone https://github.com/pikvm/os.git
                                        
                                        git clone is used to create a copy or clone of os repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with os https://github.com/pikvm/os/archive/master.zip
Or simply clone os with SSH
                                            [email protected]:pikvm/os.git                                    
                                    If you have some problems with os
You may open issue on os support forum (system) here: https://github.com/pikvm/os/issuesSimilar to os repositories
Here you may see os alternatives and analogs
core raspberry-pi-os gpiozero gogs netdata openFrameworks qt openauto pi-hole rpi-appliance-monitor pi-web-agent glslViewer iot-433mhz Home-Monitoring-Raspberry-Pi-Node flash cuberite johnny-five gobot cylon blynk-library blynk-server PJON audio-reactive-led-strip mycroft-core grafana-on-raspberry hunter Home-AssistantConfig BerryNet periph image-builder-rpi