You'll need to have Node installed to run these tests. Follow the intructions on Nodejs.org to install if you don't already have it installed.
You will also need Grunt CLI installed (globally) too :
npm install -g grunt-cli
You will then need to intall the dependencies with :
npm install
Once you're ready to get going you can start the server with :
grunt
A local server will start and your default browser will open on the right page, if your browser doesn't open then you can open your browser to : http://0.0.0.0:9001
You will now have a bunch of failing tests. There are two pages of tests, you can get to the second page with the link at the bottom.
You need to write the code to make as many of the tests pass as you can. The specs are in the html in a script block - you need to write your code in the index.js file. Any time you modify this file and save - grunt will re-run and reload your browser window.
You have access to the lodash utility library, should you wish to use it.
You should spend about an hour on this activity - complete as much as you can.