Hello there, @greenl ...
Sorry to see that your question has been sitting out here unanswered since the beginning of August. You may need to first download your files from My Drive before you can upload them into Canvas. I don't know that you can simply transfer files from a cloud service into a Canvas course...at least I've never heard of that being done before.
Sorry I don't have better news for you, but I hope this will be of some help to you. Take care...be well.
