...

Installation Instructions

Server-side OfficeWriter for SSRS 2012 in Native Mode 

Perform a custom setup with the OfficeWriter installer to install OfficeWriter for SSRS automatically, or run through the steps to install manually.

Installing for SSRS 2012 with SharePoint Integration

If you are running SSRS 2012 in SharePoint integrated mode against SharePoint 2010 or 2013, there are a separate set of instructions for manual installation.

...