Scenes Vs. Slides What Why When??

Hello Community,

I am having a hard time understanding the difference (from the learner POV) regarding scenes vs slides. 

I am creating content that takes learners from one "Home" slide to a Topic slide presenting topics A-B-C using buttons.  The topic pages will have 3 buttons to go to a slide designated to the topic with 4 sub-categories to click on for more (different types) of information.  This means there are 8 slides per topic (possibly even more once I start adding the content)

I cant make the tree here but for example Topic A

Topic A - Click button on topic from home page to get here

       1A - Info page Click one of 3 buttons to learn more about the 3 subtopics                    found in topic A

       1A - Learning Page with 4 buttons for EACH subtopic

           1A-1    1A-2    1A-3  1a-4 - These are the subtopic final learning pages

       2A

           2A-1    2A-2    2A-3  2a-4

       3A

            3A-1    3A-2    3A-3  3a-4

I THINK it's easier to create scenes for each topic (A,B,C), BUT I do not know how this works for learners.  I will not have a play button (next, previous), instead, the learner has to click "go back" button, or "Home" button.  

I am only on Day 2 of using Storyline360 and hope my explanation above makes sense. Any input would be appreciated.