Q: have one photo/video thats not uploaded how do i find it

Uploading I assume you mean to iCloud as that's the nature of the Apple Support document you reference.   I'm assuming you are trying to send it into your iCloud with iPhoto?  If that's the case, you probably want to check the iPhoto reference of the file.  One of the menu items of iPhoto offers "show in Finder."  That should show you where the original is.  You could always drag it into your iCloud iDisk using the Finder to the place Apple uses to distribute the photos on iCloud.    iPhoto while it may make some things easier, the feedback is not always great with large items.     Note, your speed sending data to iCloud is usually slower than receiving it from iCloud.

If my advice doesn't help, please post to the Photos forum:

Photos for Mac