PRO SITES - Editing the templates of the different pages

Hi guys!

I would like to know how can I edit (without modyfing the core files of PRO SITES) the files that generate the templates of:
01. Checkout page (with the pricing table)
02. Thank you page
03. Error page

Can I create a folder in my child theme for my main blog and put specific files into it?

For PRO SITES to suit my needs I need to edit every aspect of these pages.

I'm working on xpresso.pl domain - you have support access granted if you need to check anything.