Tree & Mountain - Sugar Stencil

Not sure how this works.

This is a nice quality stencil but not sure how it’s supposed to work. It would be nice if there was a tutorial video for this particular stencil. When airbrushing or royal icing for that matter, it seems like the open part should be under the mountain or under the trees. The middle of this stencil should not be solid. This stencil is now useless to me . I need my trees to be green not the sky above the tree line. Or I need someone to just tell me how this should work because I can’t seem to figure it out. Very disappointed in this purchase. I bought this for a specific set. I’m working on and I had to scrap the whole idea and figure something else out after several practice attempts. Nothing worked.