I screwed 2x4s directly to the stucko. I then used 2x2s horizontally where the 3 4ftx8ft painted panels would intersect. Dry wall screws anchored the panels to the frame. The lower horizontal beam was then secured with another 2x2 at a 45° angle to connect it to the 2x4s. The portion of the horizontal beam that was in the mouth was then cut out. There may be an easier way to do this but I had no help so I had to do it in pieces like this. It may be easier to build the entire unit and then anchor it to the house. To protect it from water I draped some plastic over it. A lot of the plastic got blown off however no damage occurred.
I hope that helps