Theme allows to create additional side menus, e.g. this page has “Table of contents” on the right. To create Side Menu, follow these steps:
Create new menu
Go to WP admin > Appearance > Menus screen and create new menu.
Add menu elements
Add some menu links and save your menu.
Add menu widget to the side widget
Navigate on WP admin > Appearance > Widgets screen and add “Custom menu” widget to any of available sidebars, then choose your menu in Settings and save Widget Options.