roles and capabilities

Hi, I am just creating my first web page. It will be a mix of a blog and forum, where I will be the main admin and I will enable other people to post their own blogs to the page where I will post my blogs, after my approval.
I am not quite sure what exactly are the capabilities of various roles. I have checked the site already: https://codex.www.ads-software.com/Roles_and_Capabilities

When talking about managing their own posts in Editors, is this meant their comments under the blog or the actual blog posts? I want people to be able to write a blog, but it will not be published until I will approve it. But until then they are free to write, edit, insert pictures or links, still in draft, for example. And of course, people will be free in managing their comments under the actual blog posts.