I`m trying to create a game with a map, that is dragable with the mouse with some clickable “buildings” on it.

So I know I need to add the cameras viewport lower left corner coordinates to the mouse position, to get the world and screen coordinates adjusted.
But i don´t know how to do this, like how to manipulate the mouse coordinates in the on_click / UIMouseEvent and how to constantly add the adjustment to the current mouse position to cover hover events as well.