The best way to install Devrun/sandbox is using Composer:
composer create-project devrun/sandboxwithout packagist
composer create-project devrun/sandbox sandbox --repository="{\"url\": \"https://github.com/developer-run/sandbox\", \"type\": \"vcs\"}"
composer create-project devrun/sandbox sandbox --repository="{\"url\": \"https://github.com/developer-run/sandbox\", \"type\": \"vcs\"}" --stability=dev --remove-vcs