How to download and setup gd
Open terminal and run command
                                            git clone https://github.com/chuck1024/gd.git
                                        
                                        git clone is used to create a copy or clone of gd 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 gd https://github.com/chuck1024/gd/archive/master.zip
Or simply clone gd with SSH
                                            [email protected]:chuck1024/gd.git