I don't understand what are you trying to accomplish, please send more details: "a single blog for each page"? Are you referring to a single blog post - in our terminology, blog is a collection of individual blog posts (articles)? Changing the PageSize property of the BlogPostList would basically acoomplish your goal (displaying a single article per page).
A blog slug is a title of your blog that is encoded so it is suitable to be displayed in the URL of your blog. Slugs are used wherever search engine optimization (and basic human readability) are important, all special characters are removed or replaced, spaces are replaced by dashes, etc.