How to translate product catalog plugin

I would like to translate my product catalog from english t chinese, I’ve read the plug-in manual but I still don’t understand how I can do it.

It says in “plugin FAQ”:

“All translations are given with the free download. After downloading the lite version of the product catalog, you will be able to extract the files onto your server. The specific files that you are interested in are under ultimate-product-catalogue > lang. For example, if you are searching for the Greek translation files, they should be named “UPCP-el_GR.po” and “UPCP-el_GR.mo”.

As English is the default language for WordPress, you’ll need to play with a little code to force WordPress to recognize the translated files.In order to do this, you’ll need to FTP into your WordPress install and open up the wp_config.php file and add this line of code:

define (‘WPLANG’, ‘el_GR’);

Adding this line tells WordPress you want to use translation files for Greek. Since you’ve translated only your plugin and not your WordPress backend, your plugin will display in Greek but your WordPress admin area will continue to display in English.”

How do I find “ultimate-product-catalogue > lang” and what is “FTP”?