You just set the values in the .htaccess
php_value memory_limit 4294967296
php_value post_max_size 1073741824
php_value upload_max_filesize 524288000
php_value max_input_vars 1000
To verify that the new setting is active, create a PHP test file that contains the following code in the same directory where the .htaccess file is located:
<?php phpinfo(); ?>