Open the theme at the Home template.
Add several Section controls. These are the section of which the One Page website will consist.
Specify Section ID:
The Section ID is the anchor to which the page should scroll once you click on the menu item.
Add desired content into the Sections.
For example, you can add WordPress Widget Area controls using Insert tab. Later you can add any Wordpress widgets into the appropriate widget areas via WP Appearance >> Widgets.
Add the Horizontal Menu control from Insert >> Navigation >> Horizontal Menu if it does not exist.
Add "Smooth Scrolling" extension to the Horizontal Menu. You can also add "Fix on Scroll" extension if needed.
Enable "Scroll Spy" plug-in under the Themler Home tab >> Settings.
Go to WP Admin Panel >> Appearance >> Menus and create a new menu. Use custom links to create it, setting URL links as anchors links, e.g.
Set this menu as the Primary Navigation menu.