How do I control how many posts appear on the blog and category pages?

Blog Page

To control the number of posts that appear on your blog page template, you'll navigate to GENESIS>THEME SETTINGS and scroll down to the Blog Page Template box and set the number of posts you'd like to appear there.

Archive & Site settings

To control how many posts display on your archive/category pages you'll navigate to SETTINGS>READING and enter the number of posts you'd like in this section.