1. Go to the page you want to enable the smooth scroll.
2. Do right click on the anchor links and inspect
3. In the div of your anchor links take either the CSS class or ID of the div.
Example: In our case we take the CSS class .um-smooth-scroll-links
4. Now add this CSS class in the admin field. Eg. .um-smooth-scroll-links .Please, add only one selector of the div. In our case, we will add only: .um-smooth-scroll-links