KML With Google Map

I need to provide a mockup of a Google Map that loads trees via a KML files. I want a Google Map on the left hand side of the screen. I want three checkboxes with labels "Layer1", "Layer2", and "Layer3" on the right hand side. When a checkbox is checked, I want you to load KML file #1. The tree markers should show up on the map. Same thing for the other checkboxes. When unchecked, the markers for that layer should be removed from the map. This is example data but I would like the tree markers to be from a similar region. Perhaps different cities. Simple as that. I am not too picky about that detail.