I have made few medieval build prefabs so that its fast and easy to build When it comes to corners all you need is just overlap them like in a picture below. Most of the peaces are 5x5 size wooden platform is 5x5x5 Also added few roof peaces.
I compressed all blueprints in a rar. file because its more then 10 of them all you need is extract them in you preferred folder.
I hope it works I haven't compress files before let me know if its working or not.