OpenCart Flat Rate shipping module cloning

I have some online shop based on ocStore which is Russian version of the OpenCart CMS. I will show the example of how to clone the Flat Rate shipping module. Here is the original module

But what to do if you need to rename the module or clone it with another value?

Let's find all files related to flat module

Now we need to copy it one by one to the new name flat_custom1 in my case

Next replace all occurrences of the flat keyword by flat_custom1 in all files we just copied.

Also all classes with name ending to Flat should be replaced by the new name FlatCustom1. All names and other strings located in the language folder, for admin view and English language the file is ./public_html/admin/language/english/shipping/flat_custom1.php

heading_title is the name, which will be shown in the Shipping section of the Admin view.

Customer view file is ./public_html/catalog/language/english/shipping/flat_custom1.php

Here you can change title and description for your new Flat Rate shipping module, it will be shown to customers during checkout. 
After that new cloned module should be available in the Shipping section in the Admin view with the name specified above.