adding new custom page is just like adding the page of about.markdown, which is already in project directory.
create new page in any project location except the ones start with_ and add the frontmatter of layout: page(different from layout: post) and title: the title.(permalink is optional)

---
layout: page
title: anytitle
permalink: /anytitle/
---

A new customized page shows on navigation

the frontmatter of layout and title will allow the page to be added on navigation.
to customize the style of the new page, add ./assets/main.scss.
in the main.scss file add frontmatter and @import like below.
write custom style below in the main.scss file.

---
# Only the main Sass file needs front matter (the dashes are enough)
---

@import "minima";
/* custom style goes below */

Resources: