You should clone this repository to any location on your system, then run the composer install command within the cloned directory so the installer's dependencies will be installed. Finally add that location to your system's PATH so that the spark executable can be run from anywhere on your system.
After purchasing a Spark license, run the spark register command with your API token generated from the Laravel Spark website.
spark register token-value
Once your Spark client has been registered, you can run the new command to create new projects:
spark new project-name
After the project has been created, don't forget to run your database migrations!