Patrick, I see you got the sound set selection figured out (double click the field) from the Sibelius chat. And there's no need to use Manual Sound Sets with this Template if all is setup correctly.
My response from the chat: "You need to open 'VDL_Template_7.0a.sib' in order to see the instruments from the Template (custom ensemble). Please review the setup instructions in the Readme file. Also, read Appendix C for instructions on how to Export Manuscript Paper from the Template."
Kent, right under the post text box, click "Additional Options" to attach files. If your Windows 7 is 64bit, you need to put only 64bit .dll plugin files in the Avid VST folder. Once you know you have the right Kontakt Player VST files in place, restart Sibelius. In the Playback Configuration dialog, double click the field under Sound Set to get the sound set drop down list. If you still don't see it at this point, then you need to double check where you've placed the XML sound set file.
Please thoroughly review the documentation. Come back here (start a new topic if necessary) if you do in fact need further clarification.
Hugh