This FAQ relates to the downloadable Easy Internet WYSIWYG Web Builder available from http://www.easyinternetsolutions.co.uk/wsb
Select View->Page Properties from the menu and edit the page width or height. You can also use the ruler 'trackers' to resize your page size.
Note that these settings do not change the final output size of your HTML page, because your browser only displays the area of your page that has visible objects.