No theme in hugo Hugo does not have to use a theme, even though it asks you to go download one in the installation process.
Instead you can add your own design to the template files and use a static css with static images and javascript. If you like more control over your site and a little uniqueness, like I do, then this is the way to go.
I often start off learning something by working backwards.
Adding a theme to your site There are many tutorials out there about starting off with Hugo, but nearly all of them take you through installing and then ask you to select a Hugo template. Now lets be honest there are not that many of them and most of what is available are not the best designs. This is one area that really needs some work.
To ensure this tutorial covers all angles this page will discuss adding a theme to your hugo.
What are partials? Partials are chunks of code that you will use multiple times throughout your site. The header or nav or even footer are the most common ones.
Rather than having to code these in every page you simply code them once. This also helps a lot if you need to change them after you have them in many pages.
How and when to use them. It makes sense to create a partial every time you think you may need to use this code in more than one place.