// How to create a TDAmeritrade API client.
$userName                     = 'joeuser123';
$accessToken                  = 'stringFromTDAmeritradeAuthentication';
$refreshToken                 = 'anotherStringFromTDAmeritradeAuthentication';
$refreshTokenExpiresInSeconds = intFromTDAmeritradeAuthentication;
$debug                        = false;
$tdaClient = TDAmeritradeAPI( $userName,
                              $accessToken,
                              $refreshToken,
                              $refreshTokenExpiresInSeconds,
                              $debug );