I have been reading the docs on bulk course uploads, and it appears that I should be able to use the process to upload backup files. I have the files on my local machine, and when I add the full path I get a message in the status field "Cannot read the backup file" they are all mbz files that were downloaded from the production site, and I am trying to upload them to the sandbox.
I have two semesters of classes that need to be done, but would rather not do them one at a time