Get a piece of pine the size you want. Use a fresh utility knife for the horizontal joints, sharp flat blade screwdriver for the vertical joints. Have at it. Knock a little off the corners here and there to age it. You don't want it perfect. Develop a crown on the top you like
When done, paint it with something like Floquil Boxcar Red. Wipe some latex white paint on into the joints, then quickly off. Some black on top.
You'll be surprised how much fun it is!
Okay John, you have our attention. Kindly share some of the steps in constructing this nice building. Great roof. Or start a thread with a lot of details. Thank you, John