This site uses Jekyll to generate the HTML. Please see the documentation there for how things work together.
For adding a new blog post see the Jekyll guide for Writing posts.
The tl;dr version goes something like this:
o create a new post, all you need to do is create a new file in the _posts directory. How you name files in this folder is important. Jekyll requires blog post files to be named according to the following format:
YEAR-MONTH-DAY-title.md
Where YEAR is a four-digit number, MONTH and DAY are both two-digit numbers.
The only extra thing that this blog does that is not default in Jekyll is to add an author field to the YAML front matter, this is inserted into the blog post as a byline.
Out typical front matter would look like this:
---
layout: post
title: This is the title of the post
author: Coz Worthington
---