Make a backup of your project before following this guide.
Go to the BuildParts/BuildParts folder and copy the video below.
Next go to the BuildPartList and copy the videos below.
Next go to the BP_BuildingMenuPageTwo and select the TriangleFloor window segment and set the settings shown in the image.
Click save all in your content browser and close the project. Then download and unzip the folder linked below.
Then go to your projects folder, this is the one that has the Content folder in it and copy the video below by copying and pasting the Content folder from the download into the project, it will ask you to replace files this is fine, select to replace the files like the video.
To place the new shutters build part use the building plan and navigate to the 2nd page and select the new shutter build part. These build parts can only be placed in window frames, and can be opened and closed by any player.