To Modify a content page on your site you need to know that all standard pages are called Content Items. So to bring up a list of all the pages on the site you will use the Content menu.

Select All Content Items from this menu.

Click on the name of the page you would like to alter and the edit window for that page will load.

From here you can alter any of the information on the page with the Intro text window. Once you are satisfied with the alterations you have made you need to click the Save button at the top right of the screen.