No boards under the unit itself. The front half is sitting on the wall. Then I attatched the back of the case to the brace by screwing it down to the brace from inside the case. Then I slid the unit into the case. Does that make sense? Hard to explain.Hey...I take offense to that!
In your picture....is there any boards from the window to the end of unit or did you just attach the 2x4s to the back of the unit with nothing more underneath from window to the end?