The Settings admin screens are among the first, on a fresh WordPress install, that a user will visit before they open their site’s doors up to the public. In the
Settings > Reading screen, the user is able to adjust the “Blog pages show at most” option. Defaulting to 10 posts per page, its left as an exercise for the theme designer to implement the actual, front-facing paging links.
From the index listing page of your theme, you’ll need to navigate to the set of posts available. i.e., from posts page #1 to posts page #2. In addition, because its great UX, its worth giving a thought to post-to-post navigation (adjacent post navigation). That is, from any given entry, a user should be able to navigate to the immediately adjacent posts on either side (if chronologically ordered, previous post or earlier post).
Unless you’re implementing infinite scroll or something similar (and even then), your default blog/index view will need to be paginated.