Help in modifying the Plugin

[casper]

Hello my friends

I have a website and I offer my work, which is the Arabization of free foreign templates into the Arabic language and put them for free download.
I installed the demo_theme on the site to display these templates, but my work is run in the basic language of the template and not as I want it is the language and the Arabic language I worked on.

Can I edit this add-on to display templates and language as I want?

If this modification is possible, the add-on link can be downloaded and modified to serve me.

https://market.osclass.org/plugins/miscellaneous/demo-theme_15

thank you