Thank you for reaching out. Could you please share screenshots of the issue you’re experiencing? Additionally, at which step does the process get stuck?
It was, on the day of writing the post, getting stuck on step 5 - the upload wheel just kept whirring. However, I have just tried this again this evening and have been able to import several Jamboards in one go, so all is well! Perhaps something to do with my account only just being created (I say this as the dashboard looked more complete than it did last week when logging in).