There are a few videos online:
Squidgy has a tutorial series that would probably be best: https://www.youtube.com/watch?v=HUZFeABbDdg
There is also the video we made: https://www.youtube.com/watch?v=wkFnSOTul4w
Unfortunately these are the old style world builder but not too much has changed since then. If you do have any trouble please message me and I can help you with what you need. Maybe we should make a more up to date tutorial, split into episodes rather than being over an hour long.
If you do get into creating worlds and biomes, we would love to have a look at them. We plan to use some community made biomes to help create our words! If you need more information on that, this might be useful: Making Worlds for the Game
Hope the links help!!!