Static Page: Display more portfolios

Check the FAQ on the theme page:
https://wptheming.com/2010/07/portfolio-theme/

Under the heading: “How do I change the number of portfolio items per page?”

function mytheme_posts_per_page() {
     return '12';  // Return however many items you choose
}
add_filter( 'portfoliopress_posts_per_page', 'mytheme_posts_per_page' );