Crystal Ball is a watchdog utility tool for watching changes to crystal source files and shard.yml and recompiling or updating the project according to the changes. Any reports from either shards or crystal compiler will be shown in the window.
Run the install scripts and it'll setup your bash profile to export to the path environment variable the path to the built binary. If you're not comfortable with that or it's not what you want, run shards build and proceed to add the binary to your path however you wish.