Setting the property values
$person->set('first_name', 'Bob');
$person->set('last_name', 'Bla');
$person->set('middle_name', 'La');
$person->set('date_modified', date('Y-m-d H:i:s'));
$person->set('dob', '1971-07-22');
$person->set('gender', 'M');
$person->set('blood_type', 'AB-');
$person->set('password', md5('b0bl4bl4'));
$person->set('username', 'boblabla');
$person->set('security_level', 1);
At this point, we have a transient instance that does not persist in the database. For this you will need to have one more line of code which will persist the object instance to the database.
$person->save();