Hugo uses the excellent Go html/template library for its template engine. It is an extremely lightweight engine that provides a very small amount of logic. In our experience it is just the right amount of logic to be able to create a good static website.
While Hugo has a number of different template roles, most complete websites can be built using just a small number of template files. Please don’t be afraid of the variety of different template roles. They enable Hugo to build very complicated sites. Most sites will only need to create a /layouts/_default/single.html & /layouts/_default/list.html
If you are new to Go’s templates, the Go Template Primer is a great place to start.
Primary Template roles
There are 3 primary kinds of templates that Hugo works with.
Render a single piece of content
Page that list multiple pieces of content
The homepage of your site
Supporting Template Roles (optional)
Hugo also has additional kinds of templates all of which are optional
Common page parts to be included in the above mentioned templates
Different ways of rendering a (single) content type
A list of the terms used for a specific taxonomy, e.g. a Tag cloud
Other Templates (generally unnecessary)
Used to render all rss documents
Used to render the XML sitemap
This template will create a 404.html page used when hosting on GitHub Pages
This template will override the default page used to create aliases of pages.