You will need Composer to install Radar.
Pick a project name, and use Composer to create it with Radar; here we create
composer create-project radar/project example-project
Confirm the installation by changing into the project directory and starting the built-in PHP web server:
cd example-project php -S localhost:8080 -t public/
You can then browse to http://localhost:8080/ and see JSON output:
You can also browse to http://localhost:8080/your-name and see modified JSON output:
You can read the documentation here.