It is designed to be simple to include into any website that is built using Vapor using just the Vapor Provider. It can be added to a path in a site or can even be used as the main site itself.
There is an example site on Github that demonstrates how to integrate SteamPress into a site, including all the Leaf templates and how to use them. It is a good starting place to clone and get up and running quickly. This site is actually the example site deployed!
The example site also includes shows how to integrate Vapor Security Headers and how to have custom error pages in Vapor.