Hey Max4dmoon,
So far I have no experience with them since they are relatively new (and there is already too much to learn :p), but there is a tutorial from the Doc’s available now, which you can find here.
The only other tutorial I know of was done during one of the recent twitch streams with Dan Hertzka, starting at the 18:00 minute mark of video: https://www.youtube.com/watch?v=dsrZgmv23Yc
It is basically created through the new “Widget” blueprint component and then placing that blueprint into the world, the rest is the usual UMG design.
Hope that helps!