How to display only the first part of a page/post

Hi Guys, i’m assuming this will be an easy one… i have a theme where on the homepage you can insert a query to display a page, so if you insert “page_id=102” it will display the page content there, but on the theme demo, it only displays a short section, you have to click the “Learn more” button to be directed to the page, what code do i need to add etc to make it do this, the demo site is: http://www.population-2.com/dev/peekaboo-wp/

On the homepage at the bottom left it shows “Our school” and only a small section, the theme says to enter the page id in the space provided and use WP Codex for everything else, never used it before so looking for an answer..

Thanks in advance guys… 🙂