You need a window to start with. As with all windows they have to manage their size, position and drawing. Maybe your window can be an owner draw listbox window, or maybe it needs to be a complete custom window, I don’t know.
Then you have to handle the data that you want to display in the window. Where it comes from how do you cache or even persist it?
Then you would integrate it in some way with the appropriate events of the edit box.
There is no cookbook way to accomplish your goal. If you gave 100 developers an the un-parameterized task that you gave us they would likely do it 100 different ways.
-pete