Slide-up view in Flutter

I'm trying to make something similar to google/apple maps screen in flutter. I just started experimenting in Flutter and I have a hard time understand that "Draggable widget". Could someone give me example code how they made their slide-up view, I can learn from? I can't find any.

How do you use draggable in flutter?

When a draggable widget recognizes the start of a drag gesture, it displays a feedback widget that tracks the user's finger across the screen. If the user lifts their finger while on top of a DragTarget, that target is given the opportunity to accept the data carried by the draggable.

There's also the sliding_up_panel Flutter library you could use to implement the same sort of design that Google/Apple Maps uses.