Coos, perhaps start by letting us know what the overall weight is of this items you've got. Also a good way to look at what size to make this one is to look at other designs using the same power unit as to wing area and weight.

Being a single wing you'll want to size it a bit bigger for area than the equivalent standard configuration of wing and stabilizer. I like to think of it as needing to have more area because part of the wing surface at the rear is acting like the horzontal stabilizer. But the real reason is due to the flying wing needing to use a reflexed positive pitch stability airfoil that is not able to reach as high a lift coefficient as a "regular" airfoil so to compensate a little more wing area is used to be able to slow down to the same speed.

Same for the duct inlet and outlet areas. For stuff like this it's nice to plagarize from other successful designs if you can't get any meaningful data from the maker.