Here I am giving a brief idea of creating a custom module for newbie.

For taking an example, I am creating a list of contents of my custom content type.

However for creating custom pages, we can use Views module and it is highly customizable. But I am creating this list using custom module for better understanding.

So for creating a start, I am taking a content type "Downloadproduct" and I have to create list of all content of this type with a download link. For this I am assuming that you have created a "Downloadproduct" content type.

Step 1: Create a folder "mydownload" under "/sites/all/modules" folder.

Step 2: Create 3 blank files mydownload.info, mydownload.module, mydownload.tpl.php

Step 3: Add following code into mydownload.info:

; $Id: mydownload.info some_more_info
name = "My custome module module"
description = "Basic custom and hook functions to add a custom list"
package = "Mydownload"
core = 7.x 

Step 4: Open mydownload.module file and add following code in it:

<?php
// $Id: mydownload.module 
/**
 * @file
 * Basic hook funcions related modification.
 *
 */
function mydownload_menu() {
  $items = array();
    $items['mydownload'] = array(    //This will be url of your page
        'title' => t('Download products'),  //This will be title of your page
        'page callback' => 'mydownload_downloads',  //You have to create a function for your logic and data
        'access callback' => TRUE,
        'type' => MENU_LOCAL_TASK,
    );
    return $items;
}

/**
* function for list all downloadable product
**/            
function mydownload_downloads() {
  drupal_set_title('Download Products');
    $query = new EntityFieldQuery();
    $query->entityCondition('entity_type', 'node')
            ->entityCondition('bundle', 'downloadproducts') //your content type
            ->propertyCondition('status', 1);

    $result = $query->execute();
    $nids = array_keys($result['node']);
    //echo "<pre>"; print_r($nids); die;
    $nodes = entity_load('node', $nids);
    //echo "<pre>"; print_r($nodes); die;

    return theme('downloads', array('nodes' => $nodes)); //From here you are calling mydownload_theme function 
}


/**
* Implementation of hook_theme to assign view file
**/    
function mydownload_theme() {
  return array(
    'downloads' => array(
      'template' => 'mydownload',  //you have assigned html file here
      'arguments' => array('nodes'=>NULL) // Variable passed to html file. NULL is only placeholder
    ),
  );               
}

Step 4: Now your server side code is ready and you have to theme your result in HTML template file. We have done this using mydownload_theme() function and assigned mydownload.tpl.php file for it. Now open mydownload.tpl.php and put following code in it:

<?php global $base_url;?>
<?php $themePath = drupal_get_path('theme',$GLOBALS['theme']);?>
        <?php foreach ($nodes as $node) {?>   
              // Add your html here
        <?php }?>

Step 5: Now goto your module listing page and enable module "mydownload" and access url http://mysite.com/mydownload

I hope this will help someone.

NOTE: Please check your variable names and content type names as this is only a example code base and given only for logical referal.