How to get the Initial screen location for widget, and make it possible to change it from other blueprints

I found one post on the forum that interests me. But I don’t understand where the Initial screen location variable and target screen location came from, and how it was possible to edit the Initial screen location from another blueprint.
Damage displayed - Programming & Scripting / Blueprint - Epic Developer Community Forums (unrealengine.com)

You have to expose the variable (eye dot next to them) and or create variable which you then link to the position manually.

You could create a function called ChangePositiom that utilizes the values to place the widget. If you define the variables as part of the function and pass them in during the call it can also happen without having variables directly assigned to the location.

In the case of the code presented in the post, the variables are just created and set within the widget, so you would just have to create them and set their default value to utilize them.