In this post you can get the list of files from your folder and you can download particular file.

For this you need to create two files as following.

Step1: Create one index.php file and add following code.

<?php 
$path = $_SERVER['DOCUMENT_ROOT']."/your_folder/"; 
  
$files = scandir($path);
$count=1;
foreach ($files as $filename)
{
    if($filename=="." || $filename==".." || $filename=="download.php" || $filename=="index.php")
    {
        //this will not display specified files
    }
    else
    {
        echo "<label >".$count.".&nbsp;</label>";
        echo "<a href="download.php/?filename=".$filename."">".$filename."</a><br/>";
        $count++;
    }
}
?>

Step2: Create one download.php file and add following code.

<?php
function output_file($file, $name, $mime_type='')
{
 /*
 This function takes a path to a file to output ($file),  the filename that the browser will see ($name) and  the MIME type of the file ($mime_type, optional).
 */
 
 //Check the file premission
 if(!is_readable($file)) die('File not found or inaccessible!');
 
 $size = filesize($file);
 $name = rawurldecode($name);
 
 /* Figure out the MIME type | Check in array */
 $known_mime_types=array(
  "pdf" => "application/pdf",
  "txt" => "text/plain",
  "html" => "text/html",
  "htm" => "text/html",
 "exe" => "application/octet-stream",
 "zip" => "application/zip",
 "doc" => "application/msword",
 "xls" => "application/vnd.ms-excel",
 "ppt" => "application/vnd.ms-powerpoint",
 "gif" => "image/gif",
 "png" => "image/png",
 "jpeg"=> "image/jpg",
 "jpg" =>  "image/jpg",
 "php" => "text/plain"
 );
 
 if($mime_type==''){
  $file_extension = strtolower(substr(strrchr($file,"."),1));
  if(array_key_exists($file_extension, $known_mime_types)){
  $mime_type=$known_mime_types[$file_extension];
  } else {
  $mime_type="application/force-download";
  };
 };
 
 //turn off output buffering to decrease cpu usage
 @ob_end_clean(); 
 
 // required for IE, otherwise Content-Disposition may be ignored
 if(ini_get('zlib.output_compression'))
  ini_set('zlib.output_compression', 'Off');
 
 header('Content-Type: ' . $mime_type);
 header('Content-Disposition: attachment; filename="'.$name.'"');
 header("Content-Transfer-Encoding: binary");
 header('Accept-Ranges: bytes');
 
 /* The three lines below basically make the 
    download non-cacheable */
 header("Cache-control: private");
 header('Pragma: private');
 header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
 
 // multipart-download and download resuming support
 if(isset($_SERVER['HTTP_RANGE']))
 {
 list($a, $range) = explode("=",$_SERVER['HTTP_RANGE'],2);
 list($range) = explode(",",$range,2);
 list($range, $range_end) = explode("-", $range);
 $range=intval($range);
 if(!$range_end) {
  $range_end=$size-1;
 } else {
  $range_end=intval($range_end);
 }
 
 $new_length = $range_end-$range+1;
 header("HTTP/1.1 206 Partial Content");
 header("Content-Length: $new_length");
 header("Content-Range: bytes $range-$range_end/$size");
 } else {
 $new_length=$size;
 header("Content-Length: ".$size);
 }
 
 /* Will output the file itself */
 $chunksize = 1*(1024*1024); //you may want to change this
 $bytes_send = 0;
 if ($file = fopen($file, 'r'))
 {
 if(isset($_SERVER['HTTP_RANGE']))
 fseek($file, $range);
 
 while(!feof($file) && 
  (!connection_aborted()) && 
  ($bytes_send<$new_length)
       )
 {
  $buffer = fread($file, $chunksize);
  print($buffer); //echo($buffer); // can also possible
  flush();
  $bytes_send += strlen($buffer);
 }
 fclose($file);
 } else
 //If no permissiion
 die('Error - can not open file.');
 //die
die();
}
//Set the time out
set_time_limit(0);

//path to the file
$file_path=$_SERVER['DOCUMENT_ROOT'].'/your_folder/'.$_REQUEST['filename'];


//Call the download function with file path,file name and file type
output_file($file_path, ''.$_REQUEST['filename'].'', 'text/plain');

?>

Change 'your_folder' with you folder name in both files.