The PerchAPI class is your starting point to the API. Instantiate it passing in the API version number (currently 1.0) and your app ID.
$API = new PerchAPI(1.0, 'my_sample');
PerchAPI exposes a number of methods.
This is a factory method for instantiating all the other API classes. Pass in the name of the class you wish to instantiate.
$HTML = $API->get('HTML');
A utility method to return the web path to your app.
$API = new PerchAPI(1.0, 'my_sample'); echo $API->app_path(); // echos /perch/apps/my_sample