You need to decide whether to clone using https or ssh. If the repository is public and you won't be pushing to it, feel free to use https, since you won't need to provide username or password. Otherwise (it's private or you'll be pushing to it), use ssh so that you can use your ssh key rather than providing a username or password.
The ssh URL is of the form git@github.com:username/reponame.git while the https URL is of the form https://github.com/username/reponame.git You can copy the URL from the Code↓ popup in the GitHub web interface.
From this point on, doing a save on files in your project will update your application in the browser.