How can I ensure my custom styles are not lost?

I created two custom paragraph styles in Writer, but on restarting Writer, they were gone. I repeated the procedure 4 times, with the same result. How can I ensure my custom styles are not lost?

Ubuntu 14.10, Libre Office 4.3.3.2

Custom styles are saved with your document. So when you restart Writer and open your document you will find your styles again. If you also want to use the styles in other documents, you can save your doc as a template which you can use for new documents.

Thank you.