How do I get the data from a relation field?
If you already know the custom field name then it is pretty straight forward:

$currentEntry = craft()-&gt;entries-&gt;getEntryById($id);
$relatedEntries = $currentEntry-&gt;customFieldName;


Then you could either loop through each one:

foreach ($relatedEntries as $entry) {
    echo $entry-&gt;title;
}


Or simply get the data from the first one:

echo $relatedEntries-&gt;first()-&gt;title;


Remember that all related entries come back as an array even if you have specified that the user can only select 1.

Hope this helps