Onepage Navigation addon create a float menu at the edge of the page to allow your users to easily navigate within sections of the page.
Add the addons on the page, enter the addon settings and create a new item.
Then choose the title, icon and item ID.
The item ID is very important because it will be associated with the section in which the scroll will be performed once clicked.
The item ID must not contain spaces or special characters.
Now edit the section you want to scroll to, go to the “Advanced” tab and look for the CSS ID option.
Add the same item ID entered in the Onepage Navigation widget options.
Repeat these two steps for each item you want to insert in the Onepage Navigation menu.
Each item must have a different item ID.
You can see a demo example with the final result here.