The easiest way, IMO, is to use the Pages controller (which is built-into Cake). In other words, for an about page, just go to the app/views/pages folder and create the about.ctp file. Put in it whatever HTML/PHP you'd like. Then, you can go to
http://localhost/app/pages/about and it will display the page. If you want this route to appear differently, just use the Routes configuration to make the setting. It will be through
'controller'=>'pages','action'=>'display','about'