Create a new hugo website or open your existing hugo site.

Add the theme to your hugo site

Use as a git submodule:

git submodule add https://github.com/theNewDynamic/gohugo-theme-ananke.git themes/ananke

Clone the repository (one-off, updating the theme may be harder later):

git clone https://github.com/apvarun/blist-hugo-theme.git themes/blist

Understanding the theme structure