Drupal 5 field in module to search database

Hi guys,
i am trying to complete this task (adding a field to a module) for days now but cant find any solution.

I created a module that works and shows results on my website.

My task is to add a field you can enter keywords -> press search button and get all the results listed.
The module creates a block that shows my results at the moment.

Here is what i have right now:

/**
 * Hilfe zum Modul
 * @param section - wo auf der Seite wird die Hilfe angezeigt 
 * @return - der Hilfetext des Moduls
 */

function artikelsuche_help($section='') {

  $output = '';

  switch ($section) {
    case "admin/help#artikelsuche":
      $output = '<p>'.  t("Artikelsuche nach SKU oder Artikelname"). '</p>';
      break;
  }

  return $output;
} // function artikelsuche_help



/* Mögliche Zugriffsrechte für dieses Modul */

function artikelsuche_perm() {

return array('access artikelsuche content', 'administer artikelsuche');

} // function artikelsuche_perm






/*
* Funktion des Blocks
* $op == list -> Name des Blocks in der Block-Übersicht
* $op == view -> Inhalt des Blocks der auf Seite dargestellt wird
*/

function artikelsuche_block($op='list', $delta=0) {
  // listing of blocks, such as on the admin/block page
  if ($op == "list") {
    $block[0]["info"] = t("artikelsuche");
    return $block;
  } 
  else if ($op == 'view') {
// Block Inhalt


  // Contentvariable die den Blockinhalt zurückgibt
    $block_content = '';

//AB HIER BEGINNT DER EIGENTLICHE INHALT

  
//THIS QUERY SHOULD HAVE THE VARIABLE FROM THE SEARCH FIELD IN IT


$query = "SELECT nid, title FROM {node} WHERE (type = 'content_random_products' OR type = 'content_random_stock' OR type = 'product') AND status = 1";



    // Links erstellen
    $queryResult =  db_query($query);
    while ($links = db_fetch_object($queryResult)) {
      $block_content .= l($links->title, 'node/'.$links->nid) . '<br />';
    }
 

// Wenn keine Ergebnisse gefunden wurden
    if ($block_content == '') {
    
return;
 	
    
    }
    // Block erzeugen
    $block['subject'] = 'Artikelsuche';
    $block['content'] = $block_content;
    return $block;
  }

}

Sorry for any mistakes, english is not my native language

Thanks in advance!
David

EDIT:
This is basically what i try to achieve:
https://www.drupal.org/node/57349

my version:

function quickmail_perm(){
    return array ('can send quickmail');
}

function 
quickmail_block($op = "list", $delta = 0) {
  if ($op == 'list') {
    $block[0]['info'] = t('Quickmail Block');
    return $block;
  }
  elseif ($op == 'view') {
     $block['subject'] = 'Quickmail';
     $block['content'] = quickmail_form();
      return $block;
  }
}

function 
quickmail_form($edit = null) {
 
  $form['details']['firma'] = array(
    '#type' => 'textfield',
    '#title' => t('Firma'),
    '#default_value' => $edit['firma'],
    '#size' => 15,
    '#maxlength' => 128,
    '#description' => null,
    '#attributes' => null,
    '#required' => true,
  );
  $form['details']['telefon'] = array(
    '#type' => 'textfield',
    '#title' => t('Telefon Nr.'),
    '#default_value' => $edit['telefon'],
    '#size' => 15,
    '#maxlength' => 128,
    '#description' => t('Geben Sie hier die Telefon Nr. ein unter der Sie unseren Rückruf erwarten.'),
    '#attributes' => null,
    '#required' => true,
  );
 

  return drupal_get_form('quickmail_form', $form);
}

But this just loads a few seconds and leaves my page white.
Removing the $block['content'] = quickmail_form(); line changes it so that i see my page again but without the needed fields of course.