1. Go to C:\Program Files (x86)\VstPlugins\Primer\Presets
  2. In there you should see one or more Lesson Pack folders. Each folder should contain the missing presets for that Lesson Pack.
  3. Copy the presets folder(s) to wherever you installed Primer. Put it in Primer's Presets folder there.
  4. Close and re-open your DAW and Primer