@jellycrystals May be I am missing something, but the most straightforward approach I can think of is logging into your kid's iCloud Drive from your Windows browser (via icloud.com) and uploading files.
@ravigupta His school is a Google school and it all backs up on there I think. I just wanted to throw a few movies on it for a train ride to cover no wifi times. I will have a look into it. Thanks for the suggestion 🤘
@ravigupta Yeah, not running a sever at the moment. Ended up just using Netflix d/l function. Will see what else I can do after the holiday. I am just so used to "drag and drop" life this has thrown me!