$validations = array(  
   [KEY] => array(
          [VALIDATION],
          [false/true],   # Is the field required, default is true
          [CUSTOM ERROR], # Your Custom error
  ),
);

require "class.SimpleValidate.php";

$validations = array(
  "name"   => array( "alphaSpace" ),
  "phone"  => array( "integer", false ,"Phone number is invalid" ),
);

$result = SimpleValidate::validate( $_POST, $validations );
if( $result===false )
{
  $errors = SimpleValidate::getErrors();
}