Single/One Page Custom Theme Development for Drupal 8

Hi..

I want to develop a one page/single page custom theme(from scratch) in Drupal 8. I have already developed a normal theme from scratch in Drupal 8.
In Drupal 7 I am able to develop single page website using a module : Single Page Website
(https://www.drupal.org/project/single_page_website)
But I am unable to find any tutorial to build a single page theme from scratch in Drupal 8. The D7 module is not compatible with D8. Rather there is another module name Single Page Site in D8. But I am unable to follow its configurations. Can anyone help me out with it?
I don’t want the contributed one page zymphony and parallax themes in D8.
Any help would be appreciated..!!

Drupal version: 


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