A Sitecore site can be set up by using an .exe installer, or by manual process using a zip file. The .exe will create a site for you in IIS, copy all the required files into the folder for the site, attach all the databases to a SQL Server instance that you specify, and update the connection strings in the ConnectionStrings.config.
The .exe does not have a silent install mode, so it is not recommended for automated deployments. The .zip installation is a complete .zip file of the website, databases and database files, and data folders. The .zip installation can be used with deployment automation, and provides the most flexibility for setting up your site. However, this also means that you must perform tasks such as setting up the IIS site, putting folders on the hard disk, placing files, deciding where the database files are placed, and setting up security.
Full details about the Sitecore 8 installation process are located at https://dev.sitecore.net/Downloads/Sitecore_Experience_Platform/82