Require the file in your script as follows:
require 'connection.php';
Instantiate connection class as such:
$store = new connection('Username', 'API path', 'API token');
call various methods to the connection
$store->get('RESOURCE');
$store->delete('RESOURCE');
$store->post('RESOURCE', $fields);
$store->put('RESOURCE', $fields);
If the request fails the error details will be stored in the $error var.
If the requests per hour limit reaches 100 or less the library will automatically take 5 minutes between requests in order to provide enough time for the requests to regenerate. Once the request limit is above 100 the library will resume requests at a normal frequency.