The game UI widget
Within UMG the UI screens or panels are called UI widgets. A widget can have an unlimited amount of UI elements, which include subpanels. But think about a widget as a container for UI elements.
The UI widget is an asset type, just like any other asset within Unreal. It is better to think about it as a blueprint, but a different type of blueprint. However, it shares the same methodology, which includes a designing part, where you can assemble some elements, and a logic part, where you can add logic or code for those designing parts.
Now, let's create a UI widget, which is as simple as creating an actor blueprint and can only be created from the content browser just like any other blueprint. You can pick a widget blueprint from within the User Interface submenu.
Tip
I created mine, and just named it InGameUI
. After creating it, do a double-click in order to open the UMG designer editor.
Remember to be very organized! The project is getting bigger with time, and things might...