This is the best and simplest way
Dynamic custom pages
If you need more freedom for your pages, you can create dynamic custom pages, for example to run PHP code and create special pages. This can be easily achieved following the next steps:
Go to Add new from the Pages tab on the admin panel.
Enter a custom internal name, for example my_custom_page
Enter a tittle, body could be left empty
Create your custom file, call it page-my_custom_page.php
Upload it to your theme folder. If your theme folder is sigma, upload it to oc-content/themes/sigma.