Hey @jokuja,
This post describes how to set up a site where your blog lives in its own repository but is accessed via domain.com/blog:
[Support Guide] Can I deploy multiple repositories in a single site?
In terms of blog frameworks, you may want to check out Netlify CMS (Start with a Template | Netlify CMS | Open-Source Content Management System) or some of the static site generators here:
https://www.staticgen.com/
Let us know if that addresses your question or if we can help with anything else!