1. Make a 11x7 cobblestone(Or other material) rectangle.
2. Next, add on until the 5th layer.
3. At the 5h layer you will need to use a 5x7 area of your retangle as the observatory tower. Then stack another 5 layers up, making a Floor/Roof on the 5th and 10th layers.(You can choose to make a staircase or ladder to get to each floor)
4. Now that your at the 10th layer, you should have a 5x7 area. Use a 4x5 area as the Observatory room.
5. Mal (example, cobblestone) as frames for them. It will look life 4, 5 block tall columns with glass walls. (NOTE: Make the walls 2x2 then 1x2 cobble then 1x2 glass then 1x2 cobble once more. Also keep in mind leave one wall open for to walk in or use a door.)
6. If you could understand directions correctly you will have your keep with 3 floors for a nice starter home! Images coming soon!
Credits goes to Robbylynn12!