v1.6-v1.7 how edit default prestashop theme (make it full screen)

[wels13]

I upgraded my prestashop from 1.6.4.1 to 1.7.7.1
unfortunately my original theme that I developed for my site version 1.6.4.1 did not work for the new version 1.7.7.1
and I have to create a new theme from scratch

I wanted to start by creating a duplicate of the classic theme so I can tinker with it without missing anything , so I imported the theme from the back-office and I new classic.zip file was created in the /theme directory
but when I tried to add new theme and selected the zip file from the drop-down list , I end up having both themes but the thumbnails are missing

 

[CoolT Toy]

looks like you need a developer.
in general, you need to export the theme, change the name of the theme in the theme config and change the path in all absolute paths inside the theme files.

 

[wels13]

looks like you need a developer.
in general, you need to export the theme, change the name of the theme in the theme config and change the path in all absolute paths inside the theme files.

thank you for the advice < I want to do it on my own < I'll try doing that