I'm glad to see that you're making progress.
Originally Posted by jm24
... when I added metadata in Sigil, I couldn't see where I was supposed to insert the COVER IMAGE?
The cover image is not defined in the Metadata Editor. You simply add the cover image to the Images folder in Sigil, right-click it and select Add Semantics > Cover Image
. (Sigil will automatically add the appropriate information to the .opf file and it'll show up as cover image, when you compile the ePub with Kindle Previewer or Calibre.)