How to create One page
The best way to start is to install demo content. If you want to install one page demo please refer to the article: Installing Demo Content. You will be able to see how all elements on the single page are set.
Please have a look at the following steps, how to achieve one page:
1. Insert in required shortcode section Custom ID Attribute.
2. Then in Appearance > Menus add a new custom link and as a URL insert custom ID atribute with #.