If I may....
I ma not sure, if we think about this same but read also that: https://www.joomshaper.com/blog/how-to-build-onepage-layout-using-sp-page-builder
I hope you know HTML basics, so you know that sections/rows may have its own unique ID - in SPPB you can add in Row Options then use it in button.
But if you want to add alias links to subpages - first you have to add them to menu , as menu items. Then you can copy created alias and use it in button. If you used J1.5 or 2.5 before you know what I am talking about.