The user field returns an array that looks like this:
Array
(
[ID] => 6
[user_firstname] => John
[user_lastname] => Doe
[nickname] => johndoe
[user_nicename] => johndoe
[display_name] => John Doe
[user_email] => [email protected]
[user_url] =>
[user_registered] => 2016-07-03 12:23:56
[user_description] =>
[user_avatar] =>
)
This was generated by adding the following to a template where I want to use the information
echo '<pre>'; print_r(get_field('user_field')); echo '</pre>';
Hope that helps
