Oh yes sometimes Dtubes fails, especially with biger videos... Possible that it was not your fault. :-)

I used also tutorials my first time. This looks good:

https://steemit.com/utopian-io/@nairadaddy/tutorial-how-to-upload-videos-with-d-tube

... or this also:

https://steemit.com/dtube/@cocinecomounchef/tutorial-how-to-upload-a-video-in-dtube-the-steemit-channel

See u later buddy :-) 😃