SQL Server 2012 SP1 Installation

Hello MSDN,

I have a MS Server 2012 R2 machine to which I would like to add SQL Server 2012 SP1. I do not know much about SQL Server 2012 and have some questions. What happens to the MS Server 2012 R2 installation, does SQL Server exist with MS Server 2012 or replace it? Are their different installation methods?  Where can I find complete installation instructions?

Thanks for your help.