Get the tutorial PDF and code, or download on GithHub. A more recent tutorial covering network basics with R and igraph is available here.
If you find the materials useful, please cite them in your work – this helps me make the case that open publishing of digital materials like this is a meaningful academic contribution: Ognyanova, K. (2016) Network analysis with R and igraph: NetSci X Tutorial. Retrieved from www.kateto.net/networks-r-igraph.