To create a website using Github pages, first set up your site following the 5 steps listed on Github Pages site (with video tutorial). You should then have an R repository named in the following format - githubusername.github.io - which has an index.html file in it. There is also a Quick Start guide which takes you a bit farther in the process.
One way to set up your site quickly is to use a pre-existing template, such as this one called Minimal available here.
