You asked for PHP samples and I showed you where to find some. It's unlikely that you are going to produce a very basic website, let alone a social network, unless you understand the technology required to build it.
Or do you mean social network is just a normal web site (or a collection of web sites)?
How could I know? You are the one designing this project and we have no details on what you are planning to create.
One of these days I'm going to think of a really clever signature.