To link/anchor a button to any part of the same page, you have to add an ID to the target element.
For example, if you want to link a newly added button to a specific section, you must add an ID to the section first.
To do this, open the page in Page Builder.
Right-click to edit the target element, in this case, a section.
Click Advanced tab.
Find the CSS ID field (Located right below Z-index.)
Add any name to the CSS ID field.
Click Update at the bottom to update the page.
Next, go to your newly made button and right-click to edit.
In the Link field, type # followed with the CSS ID of the target element which is the section.
Click Update to update the page once again.