If this is your first time installing a VQF plugin for QCD, then you only need to set the library plugin ordering. If you had a previous VQF plugin, you will need to follow the flushing plug-in cache directions as well.
FLUSHING QCD PLUGIN CACHE
After installing this plug-in, if you don't see the 'VQF Header Reader' plug-in listed in the Library plugins section (as referenced above), you will need to flush the plug-in cache. Open QCD->Preferences->Plugins and click the 'Flush Plug-in Name Cache' button. Close and restart QCD. The 'VQF Header Reader' plug-in should now be listed under Preferences->Plugins->Libraries.
SETTING UP VQF HEADER READER PLUGIN ORDER
After installing this plug-in, open QCD and go to Preferences->Plugins->Libraries
Move the 'VQF Header Reader' plug-in to the top of the list.
This will make QCD use the VQF Header Reader plugin for VQF files instead of other library plugins which may not read the VQF information.