Once you have it on your machine, run npm install. This will install a test runner you can use to check your code against the expected results. Make sure to read instructions carefully as the tests will be expecting code to match exactly.
There is a folder for each day. Inside are three folders 1-easy, 2-medium and 3-hard.
You can run tests to check your answers using the following:
npm run test:all This will run every single test for the entire week.
npm run test:d1 This will run all of the tests for the day 1 challenges.
npm run test:d1:easy This will run all of the tests in the 1-easy folder in day 1.
npm run test:d1:easy:strings This runs tests for a single file strings
This pattern will apply for all for days.