How to create In-Game Windows/Panels, movable and resizable?

I’ve read article on forums, where some epic developer explains, how to create some sort of In-Game windows, by creating own Slate overlay with own type of child Windows inside of it.

Is there something like solution or guide or article for UMG? or may be ready to use solution?

Examples:

  • in-game Inventory which i can move or even resize,

  • in-game skills panel which i can move

  • in-game chat window which i can move and resize.

etc.

please help, thx.