Changing number of posts that display
From Georgetown University Commons Knowledge Base
You can choose to have your list of posts be capped at a certain number, requiring blog readers to click on a "more entries" link to view older entries.
How to change the number of posts that display
Access your dashboard and find the "settings" option on the left sidebar. Under settings, select "reading." You can change the "blog pages show at most" option to reflect the maximum number of posts that you want to have display at one time.