require 'vendor/autoload.php'; // Composer ftw!
//use BitcoinPHP\BitcoinECDSA\BitcoinECDSA;
use BitWasp\BitcoinLib\BitcoinLib;
//$bitcoinECDSA = new BitcoinECDSA();
$bitcoinlib = new BitcoinLib();
//$bitcoinECDSA->setPrivateKey($private);
//$bitcoin_addr = $bitcoinECDSA->getAddress();
$bitcoin_addr = $bitcoinlib->private_key_to_address($private);
Now you just have to download the
https://github.com/Bit-Wasp/bitcoin-lib-php/blob/master/src/BitcoinLib.php
*I recommend you to use Composer, but since you're not really a programmer I'm not sure if it's worth.
One of the libraries didn't work properly with my PHP version (5.6/7), that's why I have two libraries in my script even though I only use one of them.