Help with iCloud Drive on iPad Please
 

Hardware:
Late 2009 iMac running macOS Sierra v 10.12.5
iPad 2 Air running 10.3.2
History:
Was persuaded that backing up the iMac to a Time Machine was fine, but both are in the same place! So set up iCloud Drive on iMac and ticked all the other boxes via Preferences; bought extra iCloud storage.
Ticked most of the " Apps Using iCloud" sliders.
Installed iCloud Drive on the iPad
Problem:
Can see most of what is in my iMac via the iCloud Drive on the iPad, but training vids in my "Aviation" Documents Folder do not show. Their folders are there, but there is nothing in them to play. Other Ppts etc show up fine. They are still on the iMac.
What have I done wrong? Any assistance gratefully received.
mcdhu