Create hook menu with custom module (child/%)
try to follow this code

&lt;?php
/**
 * Implements hook_menu().
 */
function example_menu() {
  // In this example, the third parameter will be passed.
  $items['admin/example/%'] = array(
    'title' =&gt; 'Example of first parameter being passed',
    'description' =&gt; 'This has a page arguments index of two because the wildcard occurs at the 3rd parameter',
    'page callback' =&gt; 'one',
    'page arguments' =&gt; array(2),
    'access arguments' =&gt; array('access administration pages'),
  );
  // The third and fourth parameters are being passed, hence we need to create an array with values 2 and 3 for the page arguments key
  $items['admin/example/%/%'] = array(
    'title' =&gt; 'Example of multiple parameters being submitted',
    'description' =&gt; 'Example of multiple parameters being submitted',
    'page callback' =&gt; 'two',
    'page arguments' =&gt; array(2, 3),
    'access arguments' =&gt; array('access administration pages'),
  );

  return $items;
}

/**
 * One parameter being passed.
 */
function one($one) {
    return $one;
}

/**
 * Two parameters being passed.
 */
function two($one, $two) {
    return $one . ' ' . $two;
}


Thank You.