The exercises are supplied as function stubs in src/session_one.ts which you are expected to fill in.
The function stubs are accompanied by tests in test/session_one.tests.ts. When a test set for a given function passes, an exercise has been completed.
npm install
npm run watchOpen the src/session_one.ts in an editor with TypeScript support (a recent version of VS Code is highly recommended), fill in the behavior to the function stubs and run the test set.
As long as there are failing tests, just keep repeating the process. Enjoy!
Please report the issues to the issue tracker.