Creating a redirect for content type conditionally
No problem bro, its pretty simple.  I'll write you a step by step tutorial as an edit. Standby.

You will need to create a preprocess function.  Add a folder and a file in your theme.  THEMENAME/preprocess/node.preprocess.inc with this code:

&lt;?php

/**
 * Implements hook_preprocess_node().
 *
 * Hyjacking the nodes normal node link if an external link is specified
 *
 */
function YOURTHEMENAME_preprocess_node(&amp;$variables) {

  $url = NULL;

  switch ($variables['type']) {
    case 'article':
      if (isset($variables['alternate_link']['und'][0]['url'])) {
        $url = (!empty($variables['alternate_link']['und'][0]['url'])) ? $variables['alternate_link']['und'][0]['url'] : NULL;
        $variables['node_url'] = $url;
      }
    break;
  }

}


My example states that In the case of a Content Type with the machine name of 'article' (yours may be different) do something.

THEN check if my field with the machine name of 'alternative_link' (your machine name will be different) has a value then do something.

It will then use the node's default $url variable.

If it is not set, it will ignore this code and leave your $url clean