This is a sample of creating a Word document with bookmark substitutions using the OpenXml SDK 2.0

My blog post with links and description 
  - Word: http://bettercoderwannabe.blogspot.it/2012/11/create-word-document-with-bookmarks.html
  - Excel: http://bettercoderwannabe.blogspot.it/2012/12/create-excel-document-with-openxml-sdk.html