How to: Install SQL Server PowerPivot for SharePoint
Microsoft SQL Server PowerPivot for SharePoint provides query processing and IT oversight of PowerPivot data in a Microsoft SharePoint 2010 farm. To add PowerPivot for SharePoint to a SharePoint farm, you use SQL Server 2008 R2 Setup.
SQL Server Setup does not install SharePoint 2010, but it can configure it for you if you have an existing SharePoint installation that is not yet configured. There are advantages to having SQL Server Setup configure SharePoint. Namely, the server is configured with settings that are either required or recommended for a PowerPivot for SharePoint deployment.
SQL Server Setup includes new setup roles for New Server and Existing Farm deployments. These options determine whether Setup configures an operational PowerPivot server, or simply adds PowerPivot server components that you configure later in Central Administration. Unless you are starting with a clean server and an installation of SharePoint 2010 (un-configured), you must use the Existing Farm installation option.
PowerPivot for SharePoint has instance name requirements. It must be installed as its own 'PowerPivot' instance. You cannot add it to an existing instance. You cannot install it with other features.
Reporting Services integration requires that you also install Reporting Services. However, because Reporting Services cannot be installed concurrently with PowerPivot for SharePoint, you must run Setup again to install Reporting Services. You can install Reporting Services before or after installing PowerPivot for SharePoint. When you install Reporting Services, do not add it to the PowerPivot instance. Use a new instance name or another existing instance name that is not PowerPivot. This allows you to upgrade or uninstall it independently of PowerPivot.
Click the following links for more installation instructions: