We use UML for statecharts and sequence diagrams.
To create Software Design Documentation for your project using LibreOffice software which is a part of our Linux installation in the Prism lab, follow these steps:
home/<your_name>/.config/libreoffice/4/user/gallery directory
(Note: if this directory does not exist, run a LibreOffice Draw program once, and it will get created automatically). On a Mac, this might be <your_name>/Library/Application Support/LibreOffice/4/user/gallery